diff --git a/Cargo.lock b/Cargo.lock
index 62a41583b..1331b0d99 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -7712,6 +7712,7 @@ dependencies = [
  "rustfs-madmin",
  "rustfs-metrics",
  "rustfs-notify",
+ "rustfs-object-capacity",
  "rustfs-object-io",
  "rustfs-obs",
  "rustfs-policy",
@@ -7757,7 +7758,6 @@ dependencies = [
  "url",
  "urlencoding",
  "uuid",
- "walkdir",
  "zip",
 ]
 
@@ -8229,6 +8229,25 @@ dependencies = [
  "wildmatch",
 ]
 
+[[package]]
+name = "rustfs-object-capacity"
+version = "0.0.5"
+dependencies = [
+ "criterion",
+ "futures",
+ "rustfs-common",
+ "rustfs-config",
+ "rustfs-io-metrics",
+ "rustfs-utils",
+ "serial_test",
+ "temp-env",
+ "tempfile",
+ "tokio",
+ "tracing",
+ "uuid",
+ "walkdir",
+]
+
 [[package]]
 name = "rustfs-object-io"
 version = "0.0.5"
@@ -9726,6 +9745,7 @@ version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "96374855068f47402c3121c6eed88d29cb1de8f3ab27090e273e420bdabcf050"
 dependencies = [
+ "futures",
  "parking_lot 0.12.5",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 0b886abbd..febbf9eec 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -35,6 +35,7 @@ members = [
     "crates/metrics", # Metrics collection and reporting
     "crates/notify", # Notification system for events
     "crates/obs", # Observability utilities
+    "crates/object-capacity", # Capacity scan and refresh core
     "crates/policy", # Policy management
     "crates/protocols", # Protocol implementations (FTPS, SFTP, etc.)
     "crates/protos", # Protocol buffer definitions
@@ -99,6 +100,7 @@ rustfs-notify = { path = "crates/notify", version = "0.0.5" }
 rustfs-io-metrics = { path = "crates/io-metrics", version = "0.0.5" }
 rustfs-io-core = { path = "crates/io-core", version = "0.0.5" }
 rustfs-object-io = { path = "crates/object-io", version = "0.0.5" }
+rustfs-object-capacity = { path = "crates/object-capacity", version = "0.0.5" }
 rustfs-obs = { path = "crates/obs", version = "0.0.5" }
 rustfs-policy = { path = "crates/policy", version = "0.0.5" }
 rustfs-protos = { path = "crates/protos", version = "0.0.5" }
diff --git a/crates/common/src/capacity_scope.rs b/crates/common/src/capacity_scope.rs
new file mode 100644
index 000000000..9f4ea49a2
--- /dev/null
+++ b/crates/common/src/capacity_scope.rs
@@ -0,0 +1,247 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::collections::{HashMap, HashSet};
+use std::sync::{Mutex, OnceLock};
+use std::time::{Duration, Instant};
+use uuid::Uuid;
+
+const CAPACITY_SCOPE_REGISTRY_SOFT_LIMIT: usize = 2_048;
+const CAPACITY_SCOPE_REGISTRY_HARD_LIMIT: usize = 4_096;
+const CAPACITY_SCOPE_TTL: Duration = Duration::from_secs(300);
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct CapacityScopeDisk {
+    pub endpoint: String,
+    pub drive_path: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+pub struct CapacityScope {
+    pub disks: Vec<CapacityScopeDisk>,
+}
+
+#[derive(Debug, Clone)]
+struct CapacityScopeEntry {
+    scope: CapacityScope,
+    recorded_at: Instant,
+}
+
+fn capacity_scope_registry() -> &'static Mutex<HashMap<Uuid, CapacityScopeEntry>> {
+    static REGISTRY: OnceLock<Mutex<HashMap<Uuid, CapacityScopeEntry>>> = OnceLock::new();
+    REGISTRY.get_or_init(|| Mutex::new(HashMap::new()))
+}
+
+fn global_dirty_scope_registry() -> &'static Mutex<HashSet<CapacityScopeDisk>> {
+    static REGISTRY: OnceLock<Mutex<HashSet<CapacityScopeDisk>>> = OnceLock::new();
+    REGISTRY.get_or_init(|| Mutex::new(HashSet::new()))
+}
+
+fn prune_expired_entries(entries: &mut HashMap<Uuid, CapacityScopeEntry>, now: Instant) {
+    entries.retain(|_, entry| now.duration_since(entry.recorded_at) <= CAPACITY_SCOPE_TTL);
+}
+
+fn enforce_hard_limit(entries: &mut HashMap<Uuid, CapacityScopeEntry>, max_len: usize) {
+    if entries.len() < max_len {
+        return;
+    }
+
+    let evict_count = entries.len() - max_len + 1;
+    let mut eviction_order: Vec<_> = entries.iter().map(|(token, entry)| (*token, entry.recorded_at)).collect();
+    eviction_order.sort_unstable_by_key(|(_, recorded_at)| *recorded_at);
+
+    for (token, _) in eviction_order.into_iter().take(evict_count) {
+        entries.remove(&token);
+    }
+}
+
+fn merge_capacity_scopes(existing: &mut CapacityScope, incoming: CapacityScope) {
+    let mut seen: HashSet<CapacityScopeDisk> = existing.disks.iter().cloned().collect();
+    for disk in incoming.disks {
+        if seen.insert(disk.clone()) {
+            existing.disks.push(disk);
+        }
+    }
+}
+
+pub fn record_capacity_scope(token: Uuid, scope: CapacityScope) {
+    let now = Instant::now();
+    let mut entries = capacity_scope_registry().lock().unwrap_or_else(|p| p.into_inner());
+    if !entries.contains_key(&token) && entries.len() >= CAPACITY_SCOPE_REGISTRY_SOFT_LIMIT {
+        prune_expired_entries(&mut entries, now);
+        enforce_hard_limit(&mut entries, CAPACITY_SCOPE_REGISTRY_HARD_LIMIT);
+    }
+    if let Some(entry) = entries.get_mut(&token) {
+        merge_capacity_scopes(&mut entry.scope, scope);
+        entry.recorded_at = now;
+    } else {
+        entries.insert(token, CapacityScopeEntry { scope, recorded_at: now });
+    }
+}
+
+pub fn take_capacity_scope(token: Uuid) -> Option<CapacityScope> {
+    let now = Instant::now();
+    let mut entries = capacity_scope_registry().lock().unwrap_or_else(|p| p.into_inner());
+    let entry = entries.remove(&token)?;
+    if now.duration_since(entry.recorded_at) > CAPACITY_SCOPE_TTL {
+        return None;
+    }
+    Some(entry.scope)
+}
+
+pub fn record_global_dirty_scope(scope: CapacityScope) {
+    if scope.disks.is_empty() {
+        return;
+    }
+
+    let mut dirty_scopes = global_dirty_scope_registry().lock().unwrap_or_else(|p| p.into_inner());
+    dirty_scopes.extend(scope.disks);
+}
+
+pub fn drain_global_dirty_scopes() -> Vec<CapacityScopeDisk> {
+    let mut dirty_scopes = global_dirty_scope_registry().lock().unwrap_or_else(|p| p.into_inner());
+    dirty_scopes.drain().collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::Mutex;
+
+    fn test_lock() -> &'static Mutex<()> {
+        static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+        LOCK.get_or_init(|| Mutex::new(()))
+    }
+
+    fn clear_capacity_scope_registry_for_test() {
+        capacity_scope_registry()
+            .lock()
+            .expect("capacity scope registry poisoned")
+            .clear();
+        global_dirty_scope_registry()
+            .lock()
+            .expect("global dirty scope registry poisoned")
+            .clear();
+    }
+
+    #[test]
+    fn record_and_take_capacity_scope_round_trips() {
+        let _guard = test_lock().lock().expect("test lock poisoned");
+        clear_capacity_scope_registry_for_test();
+        let token = Uuid::new_v4();
+        let scope = CapacityScope {
+            disks: vec![CapacityScopeDisk {
+                endpoint: "node-a".to_string(),
+                drive_path: "/tmp/disk-a".to_string(),
+            }],
+        };
+
+        record_capacity_scope(token, scope.clone());
+
+        assert_eq!(take_capacity_scope(token), Some(scope));
+        assert_eq!(take_capacity_scope(token), None);
+        clear_capacity_scope_registry_for_test();
+    }
+
+    #[test]
+    fn record_capacity_scope_merges_disks_for_same_token() {
+        let _guard = test_lock().lock().expect("test lock poisoned");
+        clear_capacity_scope_registry_for_test();
+        let token = Uuid::new_v4();
+        record_capacity_scope(
+            token,
+            CapacityScope {
+                disks: vec![CapacityScopeDisk {
+                    endpoint: "node-a".to_string(),
+                    drive_path: "/tmp/disk-a".to_string(),
+                }],
+            },
+        );
+        record_capacity_scope(
+            token,
+            CapacityScope {
+                disks: vec![
+                    CapacityScopeDisk {
+                        endpoint: "node-b".to_string(),
+                        drive_path: "/tmp/disk-b".to_string(),
+                    },
+                    CapacityScopeDisk {
+                        endpoint: "node-a".to_string(),
+                        drive_path: "/tmp/disk-a".to_string(),
+                    },
+                ],
+            },
+        );
+
+        let scope = take_capacity_scope(token).expect("scope should exist");
+        assert_eq!(scope.disks.len(), 2);
+        assert!(scope.disks.iter().any(|disk| disk.endpoint == "node-a"));
+        assert!(scope.disks.iter().any(|disk| disk.endpoint == "node-b"));
+        clear_capacity_scope_registry_for_test();
+    }
+
+    #[test]
+    fn record_capacity_scope_enforces_hard_limit() {
+        let _guard = test_lock().lock().expect("test lock poisoned");
+        clear_capacity_scope_registry_for_test();
+
+        for _ in 0..(CAPACITY_SCOPE_REGISTRY_HARD_LIMIT + 32) {
+            record_capacity_scope(
+                Uuid::new_v4(),
+                CapacityScope {
+                    disks: vec![CapacityScopeDisk {
+                        endpoint: "node-a".to_string(),
+                        drive_path: "/tmp/disk-a".to_string(),
+                    }],
+                },
+            );
+        }
+
+        let entries = capacity_scope_registry().lock().expect("capacity scope registry poisoned");
+        assert!(entries.len() <= CAPACITY_SCOPE_REGISTRY_HARD_LIMIT);
+        drop(entries);
+        clear_capacity_scope_registry_for_test();
+    }
+
+    #[test]
+    fn record_and_drain_global_dirty_scope_round_trips() {
+        let _guard = test_lock().lock().expect("test lock poisoned");
+        clear_capacity_scope_registry_for_test();
+        record_global_dirty_scope(CapacityScope {
+            disks: vec![CapacityScopeDisk {
+                endpoint: "node-a".to_string(),
+                drive_path: "/tmp/disk-a".to_string(),
+            }],
+        });
+        record_global_dirty_scope(CapacityScope {
+            disks: vec![
+                CapacityScopeDisk {
+                    endpoint: "node-b".to_string(),
+                    drive_path: "/tmp/disk-b".to_string(),
+                },
+                CapacityScopeDisk {
+                    endpoint: "node-a".to_string(),
+                    drive_path: "/tmp/disk-a".to_string(),
+                },
+            ],
+        });
+
+        let drained = drain_global_dirty_scopes();
+        assert_eq!(drained.len(), 2);
+        assert!(drained.iter().any(|disk| disk.endpoint == "node-a"));
+        assert!(drained.iter().any(|disk| disk.endpoint == "node-b"));
+        assert!(drain_global_dirty_scopes().is_empty());
+        clear_capacity_scope_registry_for_test();
+    }
+}
diff --git a/crates/common/src/lib.rs b/crates/common/src/lib.rs
index 3c532fcf0..df06c5966 100644
--- a/crates/common/src/lib.rs
+++ b/crates/common/src/lib.rs
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 pub mod bucket_stats;
+pub mod capacity_scope;
 // pub mod error;
 pub mod data_usage;
 pub mod globals;
diff --git a/crates/ecstore/src/set_disk.rs b/crates/ecstore/src/set_disk.rs
index 29877ced6..82034c058 100644
--- a/crates/ecstore/src/set_disk.rs
+++ b/crates/ecstore/src/set_disk.rs
@@ -67,6 +67,7 @@ use http::HeaderMap;
 use md5::{Digest as Md5Digest, Md5};
 use rand::{Rng, seq::SliceRandom};
 use regex::Regex;
+use rustfs_common::capacity_scope::{CapacityScope, CapacityScopeDisk, record_capacity_scope, record_global_dirty_scope};
 use rustfs_common::heal_channel::{DriveState, HealChannelPriority, HealItemType, HealOpts, HealScanMode, send_heal_disk};
 use rustfs_config::MI_B;
 use rustfs_filemeta::{
@@ -133,6 +134,36 @@ fn env_non_negative_usize(name: &str) -> Option<usize> {
     rustfs_utils::get_env_opt_usize(name)
 }
 
+fn capacity_scope_from_disks(disks: &[Option<DiskStore>]) -> CapacityScope {
+    let mut unique = HashSet::with_capacity(disks.len());
+    let mut scoped_disks = Vec::with_capacity(disks.len());
+
+    for disk in disks.iter().flatten() {
+        let scope_disk = CapacityScopeDisk {
+            endpoint: disk.endpoint().to_string(),
+            drive_path: disk.to_string(),
+        };
+        if unique.insert(scope_disk.clone()) {
+            scoped_disks.push(scope_disk);
+        }
+    }
+
+    CapacityScope { disks: scoped_disks }
+}
+
+fn record_capacity_scope_if_needed(scope_token: Option<Uuid>, disks: &[Option<DiskStore>]) {
+    let scope = capacity_scope_from_disks(disks);
+    if scope.disks.is_empty() {
+        return;
+    }
+
+    record_global_dirty_scope(scope.clone());
+
+    if let Some(token) = scope_token {
+        record_capacity_scope(token, scope);
+    }
+}
+
 fn resolved_put_inline_buffer_enabled(object_size: i64, inline_by_topology: bool) -> bool {
     if !inline_by_topology || object_size < 0 {
         return false;
@@ -1087,6 +1118,8 @@ impl ObjectIO for SetDisks {
             }
         }
 
+        record_capacity_scope_if_needed(opts.capacity_scope_token, &online_disks);
+
         fi.replication_state_internal = Some(opts.put_replication_state());
 
         fi.is_latest = true;
@@ -1681,6 +1714,8 @@ impl ObjectOperations for SetDisks {
             }
         }
 
+        record_capacity_scope_if_needed(opts.capacity_scope_token, &disks);
+
         // TODO: add_partial
 
         if dist_erasure {
@@ -1829,6 +1864,10 @@ impl ObjectOperations for SetDisks {
                 .await
                 .map_err(|e| to_object_err(e, vec![bucket, object]))?;
 
+            if let Ok(disks) = self.get_disks(0, 0).await {
+                record_capacity_scope_if_needed(opts.capacity_scope_token, &disks);
+            }
+
             let mut oi = ObjectInfo::from_file_info(&fi, bucket, object, opts.versioned || opts.version_suspended);
             oi.replication_decision = goi.replication_decision;
             return Ok(oi);
@@ -1855,6 +1894,10 @@ impl ObjectOperations for SetDisks {
             .await
             .map_err(|e| to_object_err(e, vec![bucket, object]))?;
 
+        if let Ok(disks) = self.get_disks(0, 0).await {
+            record_capacity_scope_if_needed(opts.capacity_scope_token, &disks);
+        }
+
         let mut obj_info = ObjectInfo::from_file_info(&dfi, bucket, object, opts.versioned || opts.version_suspended);
         obj_info.size = goi.size;
         Ok(obj_info)
@@ -2157,6 +2200,8 @@ impl ObjectOperations for SetDisks {
                 error = ?err,
                 "transition completed on remote tier but source cleanup failed; skipping external lifecycle transition notification"
             );
+        } else {
+            record_capacity_scope_if_needed(opts.capacity_scope_token, &disks);
         }
 
         for disk in disks.iter() {
@@ -3515,6 +3560,8 @@ impl MultipartOperations for SetDisks {
             }
         }
 
+        record_capacity_scope_if_needed(opts.capacity_scope_token, &online_disks);
+
         fi.is_latest = true;
 
         Ok(ObjectInfo::from_file_info(&fi, bucket, object, opts.versioned || opts.version_suspended))
diff --git a/crates/ecstore/src/set_disk/heal.rs b/crates/ecstore/src/set_disk/heal.rs
index 41137bfc7..ac5762e6b 100644
--- a/crates/ecstore/src/set_disk/heal.rs
+++ b/crates/ecstore/src/set_disk/heal.rs
@@ -558,6 +558,8 @@ impl SetDisks {
                             }
                         }
 
+                        record_capacity_scope_if_needed(None, &out_dated_disks);
+
                         Ok((result, None))
                     }
                     Err(err) => Ok((result, Some(err))),
diff --git a/crates/ecstore/src/store_api/types.rs b/crates/ecstore/src/store_api/types.rs
index efbcf396d..51bd69d61 100644
--- a/crates/ecstore/src/store_api/types.rs
+++ b/crates/ecstore/src/store_api/types.rs
@@ -73,6 +73,7 @@ pub struct ObjectOptions {
     pub resolved_checksum: Option<Bytes>,
     pub want_checksum: Option<Checksum>,
     pub skip_verify_bitrot: bool,
+    pub capacity_scope_token: Option<Uuid>,
 }
 
 impl ObjectOptions {
diff --git a/crates/io-metrics/src/capacity_metrics.rs b/crates/io-metrics/src/capacity_metrics.rs
index a032727ee..be659c1dc 100644
--- a/crates/io-metrics/src/capacity_metrics.rs
+++ b/crates/io-metrics/src/capacity_metrics.rs
@@ -29,6 +29,12 @@ pub fn record_capacity_cache_miss() {
     counter!("rustfs.capacity.cache.misses").increment(1);
 }
 
+/// Record how capacity cache was served to the caller.
+#[inline(always)]
+pub fn record_capacity_cache_served(state: &'static str) {
+    counter!("rustfs.capacity.cache.served.total", "state" => state).increment(1);
+}
+
 /// Record current capacity gauge.
 #[inline(always)]
 pub fn record_capacity_current_bytes(used_bytes: u64) {
@@ -55,6 +61,44 @@ pub fn record_capacity_update_failed(source: &'static str) {
     counter!("rustfs.capacity.update.failures", "source" => source).increment(1);
 }
 
+/// Record a capacity refresh request.
+#[inline(always)]
+pub fn record_capacity_refresh_request(mode: &'static str, source: &'static str) {
+    counter!("rustfs.capacity.refresh.requests.total", "mode" => mode, "source" => source).increment(1);
+}
+
+/// Record a refresh joiner waiting for an inflight refresh.
+#[inline(always)]
+pub fn record_capacity_refresh_joiner(source: &'static str) {
+    counter!("rustfs.capacity.refresh.joiners.total", "source" => source).increment(1);
+}
+
+/// Record the number of inflight capacity refreshes.
+#[inline(always)]
+pub fn record_capacity_refresh_inflight(count: usize) {
+    gauge!("rustfs.capacity.refresh.inflight").set(count as f64);
+}
+
+/// Record the final result of a capacity refresh.
+#[inline(always)]
+pub fn record_capacity_refresh_result(source: &'static str, result: &'static str, duration: Duration) {
+    counter!("rustfs.capacity.refresh.result.total", "source" => source, "result" => result).increment(1);
+    histogram!("rustfs.capacity.refresh.duration.seconds", "source" => source, "result" => result).record(duration.as_secs_f64());
+}
+
+/// Record the refresh scope selected for a capacity refresh.
+#[inline(always)]
+pub fn record_capacity_refresh_scope(scope: &'static str, disk_count: usize) {
+    counter!("rustfs.capacity.refresh.scope.total", "scope" => scope).increment(1);
+    histogram!("rustfs.capacity.refresh.scope.disks", "scope" => scope).record(disk_count as f64);
+}
+
+/// Record the current number of dirty disks tracked by capacity management.
+#[inline(always)]
+pub fn record_capacity_dirty_disk_count(count: usize) {
+    gauge!("rustfs.capacity.dirty.disks").set(count as f64);
+}
+
 /// Record capacity write activity.
 #[inline(always)]
 pub fn record_capacity_write_operation(write_frequency: usize) {
@@ -98,3 +142,33 @@ pub fn record_capacity_scan_sampling(sampled_count: usize, estimated: bool) {
     )
     .increment(1);
 }
+
+/// Record the scan mode used for a capacity result.
+#[inline(always)]
+pub fn record_capacity_scan_mode(mode: &'static str) {
+    counter!("rustfs.capacity.scan.mode.total", "mode" => mode).increment(1);
+}
+
+/// Record per-disk capacity scan statistics.
+#[inline(always)]
+pub fn record_capacity_scan_disk(
+    disk: &str,
+    duration: Duration,
+    file_count: usize,
+    sampled_count: usize,
+    estimated: bool,
+    partial_errors: bool,
+) {
+    histogram!("rustfs.capacity.scan.disk.duration.seconds", "disk" => disk.to_owned()).record(duration.as_secs_f64());
+    histogram!("rustfs.capacity.scan.disk.files", "disk" => disk.to_owned()).record(file_count as f64);
+    histogram!("rustfs.capacity.scan.disk.sampled", "disk" => disk.to_owned()).record(sampled_count as f64);
+    counter!(
+        "rustfs.capacity.scan.disk.estimated.total",
+        "disk" => disk.to_owned(),
+        "estimated" => if estimated { "true" } else { "false" }
+    )
+    .increment(1);
+    if partial_errors {
+        counter!("rustfs.capacity.scan.disk.partial_errors.total", "disk" => disk.to_owned()).increment(1);
+    }
+}
diff --git a/crates/io-metrics/src/lib.rs b/crates/io-metrics/src/lib.rs
index 04257ff4d..c75a8041f 100644
--- a/crates/io-metrics/src/lib.rs
+++ b/crates/io-metrics/src/lib.rs
@@ -74,9 +74,12 @@ pub use adaptive_ttl::{
 
 // Capacity metrics exports
 pub use capacity_metrics::{
-    record_capacity_cache_hit, record_capacity_cache_miss, record_capacity_current_bytes, record_capacity_dynamic_timeout,
-    record_capacity_scan_sampling, record_capacity_stall_detected, record_capacity_symlink, record_capacity_timeout_fallback,
-    record_capacity_update_completed, record_capacity_update_failed, record_capacity_write_operation,
+    record_capacity_cache_hit, record_capacity_cache_miss, record_capacity_cache_served, record_capacity_current_bytes,
+    record_capacity_dirty_disk_count, record_capacity_dynamic_timeout, record_capacity_refresh_inflight,
+    record_capacity_refresh_joiner, record_capacity_refresh_request, record_capacity_refresh_result,
+    record_capacity_refresh_scope, record_capacity_scan_disk, record_capacity_scan_mode, record_capacity_scan_sampling,
+    record_capacity_stall_detected, record_capacity_symlink, record_capacity_timeout_fallback, record_capacity_update_completed,
+    record_capacity_update_failed, record_capacity_write_operation,
 };
 
 // I/O metrics exports
diff --git a/crates/object-capacity/Cargo.toml b/crates/object-capacity/Cargo.toml
new file mode 100644
index 000000000..08cdda9de
--- /dev/null
+++ b/crates/object-capacity/Cargo.toml
@@ -0,0 +1,53 @@
+# Copyright 2024 RustFS Team
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+[package]
+name = "rustfs-object-capacity"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+homepage.workspace = true
+description = "Capacity scan and refresh core for RustFS."
+keywords = ["capacity", "storage", "rustfs", "scan", "metrics"]
+categories = ["filesystem", "development-tools"]
+
+[lib]
+doctest = false
+
+[[bench]]
+name = "capacity_scan"
+harness = false
+
+[lints]
+workspace = true
+
+[dependencies]
+rustfs-common = { workspace = true }
+rustfs-config = { workspace = true, features = ["constants"] }
+rustfs-io-metrics = { workspace = true }
+rustfs-utils = { workspace = true }
+futures = { workspace = true }
+tokio = { workspace = true, features = ["sync", "time"] }
+tracing = { workspace = true }
+uuid = { workspace = true }
+walkdir = { workspace = true }
+
+[dev-dependencies]
+criterion = { workspace = true }
+serial_test = { workspace = true }
+temp-env = { workspace = true, features = ["async_closure"] }
+tempfile = { workspace = true }
+tokio = { workspace = true, features = ["test-util"] }
diff --git a/crates/object-capacity/benches/capacity_scan.rs b/crates/object-capacity/benches/capacity_scan.rs
new file mode 100644
index 000000000..ca44ab2c1
--- /dev/null
+++ b/crates/object-capacity/benches/capacity_scan.rs
@@ -0,0 +1,136 @@
+use criterion::{Criterion, criterion_group, criterion_main};
+use rustfs_object_capacity::{CapacityDiskRef, scan_used_capacity_disks};
+use std::fs;
+use std::hint::black_box;
+use std::path::{Path, PathBuf};
+use std::time::Duration;
+use tempfile::TempDir;
+
+const EXACT_FILE_SIZE: usize = 4 * 1024;
+const SAMPLED_FILE_SIZE: usize = 1;
+const DEFAULT_SAMPLE_TRIGGER_FILE_COUNT: usize = 202_048;
+
+#[derive(Clone, Copy)]
+struct DiskSpec {
+    file_count: usize,
+    file_size: usize,
+}
+
+struct CapacityScanFixture {
+    _dirs: Vec<TempDir>,
+    disks: Vec<CapacityDiskRef>,
+}
+
+impl CapacityScanFixture {
+    fn new(specs: &[DiskSpec]) -> Self {
+        let mut dirs = Vec::with_capacity(specs.len());
+        let mut disks = Vec::with_capacity(specs.len());
+
+        for (idx, spec) in specs.iter().enumerate() {
+            let dir = TempDir::new().expect("create temp dir");
+            populate_files(dir.path(), spec.file_count, spec.file_size).expect("populate files");
+            disks.push(CapacityDiskRef {
+                endpoint: format!("bench-disk-{idx}"),
+                drive_path: dir.path().to_string_lossy().into_owned(),
+            });
+            dirs.push(dir);
+        }
+
+        Self { _dirs: dirs, disks }
+    }
+}
+
+fn populate_files(root: &Path, file_count: usize, file_size: usize) -> std::io::Result<()> {
+    let payload = vec![b'x'; file_size];
+    let shard_count = (file_count / 512).clamp(1, 256);
+
+    for shard_idx in 0..shard_count {
+        fs::create_dir_all(root.join(format!("bucket-{shard_idx:03}")))?;
+    }
+
+    for file_idx in 0..file_count {
+        let subdir = root.join(format!("bucket-{:03}", file_idx % shard_count));
+        let file_path: PathBuf = subdir.join(format!("object-{file_idx:08}.bin"));
+        fs::write(file_path, &payload)?;
+    }
+
+    Ok(())
+}
+
+fn bench_capacity_scan(c: &mut Criterion) {
+    let runtime = tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .expect("create runtime");
+
+    let exact_fixture = CapacityScanFixture::new(&[DiskSpec {
+        file_count: 10_000,
+        file_size: EXACT_FILE_SIZE,
+    }]);
+
+    let sampled_fixture = CapacityScanFixture::new(&[DiskSpec {
+        file_count: DEFAULT_SAMPLE_TRIGGER_FILE_COUNT,
+        file_size: SAMPLED_FILE_SIZE,
+    }]);
+
+    let multi_disk_fixture = CapacityScanFixture::new(&[
+        DiskSpec {
+            file_count: 4_000,
+            file_size: 1024,
+        },
+        DiskSpec {
+            file_count: 6_000,
+            file_size: 2048,
+        },
+        DiskSpec {
+            file_count: 8_000,
+            file_size: 4096,
+        },
+        DiskSpec {
+            file_count: 10_000,
+            file_size: 1024,
+        },
+    ]);
+
+    let mut exact_group = c.benchmark_group("capacity_scan_exact");
+    exact_group.sample_size(10);
+    exact_group.measurement_time(Duration::from_secs(10));
+    exact_group.bench_function("single_disk_10k_4k", |b| {
+        b.iter(|| {
+            let summary = runtime
+                .block_on(scan_used_capacity_disks(black_box(&exact_fixture.disks)))
+                .expect("exact scan");
+            black_box(summary);
+        });
+    });
+    exact_group.finish();
+
+    let mut sampled_group = c.benchmark_group("capacity_scan_sampled");
+    sampled_group.sample_size(10);
+    sampled_group.measurement_time(Duration::from_secs(10));
+    sampled_group.bench_function("single_disk_202k_1b", |b| {
+        b.iter(|| {
+            let summary = runtime
+                .block_on(scan_used_capacity_disks(black_box(&sampled_fixture.disks)))
+                .expect("sampled scan");
+            black_box(summary);
+        });
+    });
+    sampled_group.finish();
+
+    let mut multi_disk_group = c.benchmark_group("capacity_scan_multi_disk");
+    multi_disk_group.sample_size(10);
+    multi_disk_group.measurement_time(Duration::from_secs(10));
+    multi_disk_group.bench_function("four_disks_mixed_exact", |b| {
+        b.iter(|| {
+            let summary = runtime
+                .block_on(scan_used_capacity_disks(black_box(&multi_disk_fixture.disks)))
+                .expect("multi-disk scan");
+            black_box(summary);
+        });
+    });
+    multi_disk_group.finish();
+}
+
+criterion_group!(benches, bench_capacity_scan);
+criterion_main!(benches);
diff --git a/rustfs/src/capacity/capacity_manager.rs b/crates/object-capacity/src/capacity_manager.rs
similarity index 56%
rename from rustfs/src/capacity/capacity_manager.rs
rename to crates/object-capacity/src/capacity_manager.rs
index d8586770f..32cfc3c85 100644
--- a/rustfs/src/capacity/capacity_manager.rs
+++ b/crates/object-capacity/src/capacity_manager.rs
@@ -14,8 +14,10 @@
 
 //! Hybrid Capacity Manager for efficient capacity statistics
 
-use crate::app::admin_usecase::calculate_data_dir_used_capacity;
+use super::scan::refresh_capacity_with_scope;
+use super::types::CapacityDiskRef;
 use futures::FutureExt;
+use rustfs_common::capacity_scope::{CapacityScope, CapacityScopeDisk, drain_global_dirty_scopes, take_capacity_scope};
 use rustfs_config::{
     DEFAULT_CAPACITY_ENABLE_DYNAMIC_TIMEOUT, DEFAULT_CAPACITY_FOLLOW_SYMLINKS, DEFAULT_CAPACITY_MAX_SYMLINK_DEPTH,
     DEFAULT_CAPACITY_MAX_TIMEOUT_SECS, DEFAULT_CAPACITY_MIN_TIMEOUT_SECS, DEFAULT_CAPACITY_STALL_TIMEOUT_SECS,
@@ -26,12 +28,17 @@ use rustfs_config::{
     ENV_CAPACITY_SAMPLE_RATE, ENV_CAPACITY_SCHEDULED_INTERVAL, ENV_CAPACITY_STALL_TIMEOUT, ENV_CAPACITY_STAT_TIMEOUT,
     ENV_CAPACITY_WRITE_FREQUENCY_THRESHOLD, ENV_CAPACITY_WRITE_TRIGGER_DELAY,
 };
-use rustfs_io_metrics::{record_capacity_current_bytes, record_capacity_update_completed, record_capacity_write_operation};
+use rustfs_io_metrics::capacity_metrics::{
+    record_capacity_current_bytes, record_capacity_dirty_disk_count, record_capacity_refresh_inflight,
+    record_capacity_refresh_joiner, record_capacity_refresh_result, record_capacity_update_completed,
+    record_capacity_update_failed, record_capacity_write_operation,
+};
 use rustfs_utils::{get_env_bool, get_env_u64, get_env_usize};
+use std::collections::{HashMap, HashSet};
 use std::future::Future;
 use std::panic::AssertUnwindSafe;
 use std::sync::Arc;
-use std::time::{Duration, Instant};
+use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
 use tokio::sync::{Mutex, RwLock, watch};
 use tracing::{debug, info, warn};
 
@@ -297,6 +304,14 @@ pub struct CapacityUpdate {
     pub file_count: usize,
     /// Whether the value is estimated instead of exact.
     pub is_estimated: bool,
+    /// Per-disk breakdown captured from a successful refresh.
+    pub per_disk: Vec<DiskCapacityUpdate>,
+    /// Expected disk count for a complete disk cache.
+    pub expected_disk_count: Option<usize>,
+    /// Whether this update should replace the current disk cache.
+    pub replaces_disk_cache: bool,
+    /// Dirty disks that can be cleared after the update is committed.
+    pub clear_dirty_disks: Vec<CapacityScopeDisk>,
 }
 
 impl CapacityUpdate {
@@ -306,6 +321,10 @@ impl CapacityUpdate {
             total_used,
             file_count,
             is_estimated: false,
+            per_disk: Vec::new(),
+            expected_disk_count: None,
+            replaces_disk_cache: false,
+            clear_dirty_disks: Vec::new(),
         }
     }
 
@@ -315,6 +334,10 @@ impl CapacityUpdate {
             total_used,
             file_count,
             is_estimated: true,
+            per_disk: Vec::new(),
+            expected_disk_count: None,
+            replaces_disk_cache: false,
+            clear_dirty_disks: Vec::new(),
         }
     }
 
@@ -324,10 +347,27 @@ impl CapacityUpdate {
             total_used,
             file_count: 0,
             is_estimated: true,
+            per_disk: Vec::new(),
+            expected_disk_count: None,
+            replaces_disk_cache: false,
+            clear_dirty_disks: Vec::new(),
         }
     }
 }
 
+#[derive(Clone, Debug)]
+pub struct DiskCapacityUpdate {
+    pub disk: CapacityScopeDisk,
+    pub used_bytes: u64,
+    pub file_count: usize,
+    pub is_estimated: bool,
+}
+
+#[derive(Clone, Debug)]
+struct CachedDiskCapacity {
+    used_bytes: u64,
+}
+
 #[derive(Clone, Debug, PartialEq, Copy, Eq)]
 pub enum DataSource {
     /// Real-time statistics
@@ -342,7 +382,7 @@ pub enum DataSource {
 }
 
 impl DataSource {
-    fn as_metric_label(self) -> &'static str {
+    pub fn as_metric_label(self) -> &'static str {
         match self {
             Self::RealTime => "realtime",
             Self::Scheduled => "scheduled",
@@ -352,15 +392,60 @@ impl DataSource {
     }
 }
 
+const WRITE_WINDOW_SECS: u64 = 60;
+const WRITE_WINDOW_BUCKETS: usize = WRITE_WINDOW_SECS as usize;
+
+#[derive(Clone, Copy, Debug, Default)]
+struct WriteBucket {
+    second: u64,
+    count: usize,
+}
+
 /// Write record for tracking write operations
 #[derive(Debug)]
 pub struct WriteRecord {
     /// Last write time
-    pub last_write_time: Instant,
+    pub last_write_time: Option<Instant>,
     /// Write count
     pub write_count: usize,
-    /// Write time window (for frequency calculation)
-    pub write_window: Vec<Instant>,
+    /// Fixed-size time buckets for the recent write window.
+    write_buckets: [WriteBucket; WRITE_WINDOW_BUCKETS],
+}
+
+impl WriteRecord {
+    fn current_unix_second() -> u64 {
+        SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .unwrap_or(Duration::ZERO)
+            .as_secs()
+    }
+
+    fn recent_write_count(&self, now_second: u64) -> usize {
+        self.write_buckets
+            .iter()
+            .filter(|bucket| bucket.count > 0 && now_second.saturating_sub(bucket.second) < WRITE_WINDOW_SECS)
+            .map(|bucket| bucket.count)
+            .sum()
+    }
+
+    fn record_write(&mut self, now: Instant) -> usize {
+        let now_second = Self::current_unix_second();
+        let bucket_idx = (now_second % WRITE_WINDOW_BUCKETS as u64) as usize;
+        let bucket = &mut self.write_buckets[bucket_idx];
+
+        if bucket.second != now_second {
+            *bucket = WriteBucket {
+                second: now_second,
+                count: 0,
+            };
+        }
+
+        bucket.count = bucket.count.saturating_add(1);
+        self.last_write_time = Some(now);
+        self.write_count = self.write_count.saturating_add(1);
+
+        self.recent_write_count(now_second)
+    }
 }
 
 /// Hybrid strategy configuration
@@ -430,6 +515,12 @@ pub struct HybridCapacityManager {
     cache: Arc<RwLock<Option<CachedCapacity>>>,
     /// Write record
     write_record: Arc<RwLock<WriteRecord>>,
+    /// Dirty disks recorded from write-side scope propagation.
+    dirty_disks: Arc<RwLock<HashSet<CapacityScopeDisk>>>,
+    /// Per-disk cache populated after a successful full refresh and updated by dirty subset refreshes.
+    disk_cache: Arc<RwLock<HashMap<CapacityScopeDisk, CachedDiskCapacity>>>,
+    /// Whether the per-disk cache currently covers all known disks.
+    disk_cache_complete: Arc<RwLock<bool>>,
     /// Configuration
     config: HybridStrategyConfig,
     /// Shared singleflight refresh state
@@ -437,6 +528,17 @@ pub struct HybridCapacityManager {
 }
 
 impl HybridCapacityManager {
+    async fn sync_global_dirty_scopes(&self) {
+        let scopes = drain_global_dirty_scopes();
+        if scopes.is_empty() {
+            return;
+        }
+
+        let mut dirty_disks = self.dirty_disks.write().await;
+        dirty_disks.extend(scopes);
+        record_capacity_dirty_disk_count(dirty_disks.len());
+    }
+
     fn max_stale_age(&self) -> Duration {
         self.config
             .scheduled_update_interval
@@ -448,10 +550,13 @@ impl HybridCapacityManager {
         Self {
             cache: Arc::new(RwLock::new(None)),
             write_record: Arc::new(RwLock::new(WriteRecord {
-                last_write_time: Instant::now(),
+                last_write_time: None,
                 write_count: 0,
-                write_window: Vec::new(),
+                write_buckets: [WriteBucket::default(); WRITE_WINDOW_BUCKETS],
             })),
+            dirty_disks: Arc::new(RwLock::new(HashSet::new())),
+            disk_cache: Arc::new(RwLock::new(HashMap::new())),
+            disk_cache_complete: Arc::new(RwLock::new(false)),
             config,
             refresh_state: Arc::new(Mutex::new(RefreshState::default())),
         }
@@ -471,49 +576,97 @@ impl HybridCapacityManager {
     /// Update capacity
     pub async fn update_capacity(&self, update: CapacityUpdate, source: DataSource) {
         let start = Instant::now();
+        let mut total_used = update.total_used;
+
+        if !update.per_disk.is_empty() {
+            let mut disk_cache = self.disk_cache.write().await;
+            let mut disk_cache_complete = self.disk_cache_complete.write().await;
+
+            if update.replaces_disk_cache && update.expected_disk_count == Some(update.per_disk.len()) {
+                disk_cache.clear();
+                for entry in &update.per_disk {
+                    disk_cache.insert(
+                        entry.disk.clone(),
+                        CachedDiskCapacity {
+                            used_bytes: entry.used_bytes,
+                        },
+                    );
+                }
+                *disk_cache_complete = true;
+                total_used = disk_cache.values().map(|entry| entry.used_bytes).sum();
+            } else if *disk_cache_complete {
+                for entry in &update.per_disk {
+                    disk_cache.insert(
+                        entry.disk.clone(),
+                        CachedDiskCapacity {
+                            used_bytes: entry.used_bytes,
+                        },
+                    );
+                }
+                total_used = disk_cache.values().map(|entry| entry.used_bytes).sum();
+            }
+        }
+
         let mut cache = self.cache.write().await;
         *cache = Some(CachedCapacity {
-            total_used: update.total_used,
+            total_used,
             last_update: Instant::now(),
             file_count: update.file_count,
             is_estimated: update.is_estimated,
             source,
         });
 
+        if !update.clear_dirty_disks.is_empty() {
+            let mut dirty_disks = self.dirty_disks.write().await;
+            for disk in &update.clear_dirty_disks {
+                dirty_disks.remove(disk);
+            }
+            record_capacity_dirty_disk_count(dirty_disks.len());
+        }
+
         debug!(
             "Capacity updated: {} bytes, files={}, estimated={}, source: {:?}",
-            update.total_used, update.file_count, update.is_estimated, source
+            total_used, update.file_count, update.is_estimated, source
         );
-        record_capacity_current_bytes(update.total_used);
-        record_capacity_update_completed(source.as_metric_label(), start.elapsed(), update.total_used, update.is_estimated);
+        record_capacity_current_bytes(total_used);
+        record_capacity_update_completed(source.as_metric_label(), start.elapsed(), total_used, update.is_estimated);
     }
 
     /// Record write operation
     pub async fn record_write_operation(&self) {
         let mut record = self.write_record.write().await;
-        record.last_write_time = Instant::now();
-        record.write_count += 1;
-
-        // Maintain write time window (keep last 1 minute)
-        // Cap the window size to prevent unbounded memory growth at high write rates
-        const MAX_WRITE_WINDOW_SIZE: usize = 10000;
         let now = Instant::now();
-        record
-            .write_window
-            .retain(|&t| now.duration_since(t) < Duration::from_secs(60));
-        // Only push if under the cap to prevent unbounded growth
-        if record.write_window.len() < MAX_WRITE_WINDOW_SIZE {
-            record.write_window.push(now);
-        }
+        let recent_write_count = record.record_write(now);
 
-        record_capacity_write_operation(record.write_window.len());
+        record_capacity_write_operation(recent_write_count);
         debug!(
             "Write operation recorded: total writes = {}, recent writes = {}",
-            record.write_count,
-            record.write_window.len()
+            record.write_count, recent_write_count
         );
     }
 
+    /// Record write scope propagated from the storage layer.
+    pub async fn mark_dirty_scope(&self, scope: &CapacityScope) {
+        if scope.disks.is_empty() {
+            return;
+        }
+
+        let mut dirty_disks = self.dirty_disks.write().await;
+        dirty_disks.extend(scope.disks.iter().cloned());
+        record_capacity_dirty_disk_count(dirty_disks.len());
+    }
+
+    /// Record a write operation and consume any propagated disk scope bound to the token.
+    pub async fn record_write_operation_with_scope_token(&self, scope_token: Option<uuid::Uuid>) {
+        if let Some(token) = scope_token
+            && let Some(scope) = take_capacity_scope(token)
+        {
+            self.mark_dirty_scope(&scope).await;
+        }
+
+        self.record_write_operation().await;
+    }
+
     /// Check if fast update is needed
     pub async fn needs_fast_update(&self) -> bool {
         if !self.config.enable_smart_update {
@@ -529,19 +682,31 @@ impl HybridCapacityManager {
                 return false;
             }
 
-            let write_record = self.write_record.read().await;
-            let time_since_write = write_record.last_write_time.elapsed();
-
-            // Recent write, trigger fast update
-            if time_since_write < self.config.fast_update_threshold {
-                debug!("Recent write detected ({:?} ago), needs fast update", time_since_write);
-                return true;
+            if !self.config.enable_write_trigger {
+                return false;
             }
 
-            // High write frequency, trigger update
-            let write_frequency = write_record.write_window.len();
-            if write_frequency > self.config.write_frequency_threshold {
-                debug!("High write frequency detected ({} writes/min), needs fast update", write_frequency);
+            let write_record = self.write_record.read().await;
+            let write_frequency = write_record.recent_write_count(WriteRecord::current_unix_second());
+            if write_frequency <= self.config.write_frequency_threshold {
+                return false;
+            }
+
+            if let Some(last_write_time) = write_record.last_write_time {
+                let time_since_write = last_write_time.elapsed();
+
+                if time_since_write < self.config.write_trigger_delay {
+                    debug!(
+                        "Write-triggered refresh still debounced ({:?} ago, trigger_delay={:?}, writes/min={})",
+                        time_since_write, self.config.write_trigger_delay, write_frequency
+                    );
+                    return false;
+                }
+
+                debug!(
+                    "Write-triggered refresh eligible after debounce ({:?} ago, trigger_delay={:?}, writes/min={})",
+                    time_since_write, self.config.write_trigger_delay, write_frequency
+                );
                 return true;
             }
         }
@@ -560,7 +725,19 @@ impl HybridCapacityManager {
     #[allow(dead_code)]
     pub async fn get_write_frequency(&self) -> usize {
         let record = self.write_record.read().await;
-        record.write_window.len()
+        record.recent_write_count(WriteRecord::current_unix_second())
+    }
+
+    /// Snapshot the currently dirty disks recorded from write-side scope propagation.
+    pub async fn get_dirty_disks(&self) -> Vec<CapacityScopeDisk> {
+        self.sync_global_dirty_scopes().await;
+        let dirty_disks = self.dirty_disks.read().await;
+        dirty_disks.iter().cloned().collect()
+    }
+
+    /// Returns true if the manager has a complete per-disk cache and can safely refresh only dirty disks.
+    pub async fn can_refresh_dirty_subset(&self) -> bool {
+        *self.disk_cache_complete.read().await
     }
 
     /// Run a singleflight refresh. Callers either join an existing in-flight refresh or become the leader.
@@ -577,6 +754,7 @@ impl HybridCapacityManager {
             if state.running {
                 // Subscribe while holding the lock so the send that completes the current
                 // refresh cycle cannot happen before we are subscribed.
+                record_capacity_refresh_joiner(source.as_metric_label());
                 Some(state.result_tx.subscribe())
             } else {
                 // Become the leader. Create a fresh channel so that joiners from a previous
@@ -584,6 +762,7 @@ impl HybridCapacityManager {
                 let (tx, _) = watch::channel(None);
                 state.result_tx = tx;
                 state.running = true;
+                record_capacity_refresh_inflight(1);
                 None
             }
         };
@@ -603,6 +782,7 @@ impl HybridCapacityManager {
                 .unwrap_or_else(|| Err("capacity refresh completed without a result".to_string()));
         }
 
+        let refresh_start = Instant::now();
         let result = AssertUnwindSafe(refresh_fn()).catch_unwind().await.unwrap_or_else(|err| {
             warn!(error = ?err, "capacity refresh function panicked");
             Err("capacity refresh panicked".to_string())
@@ -610,10 +790,20 @@ impl HybridCapacityManager {
         if let Ok(update) = &result {
             self.update_capacity(update.clone(), source).await;
         }
+        let refresh_duration = refresh_start.elapsed();
+        if result.is_err() {
+            record_capacity_update_failed(source.as_metric_label());
+        }
+        record_capacity_refresh_result(
+            source.as_metric_label(),
+            if result.is_ok() { "success" } else { "error" },
+            refresh_duration,
+        );
 
         {
             let mut state = self.refresh_state.lock().await;
             state.running = false;
+            record_capacity_refresh_inflight(0);
             let _ = state.result_tx.send(Some(result.clone()));
         }
 
@@ -634,6 +824,7 @@ impl HybridCapacityManager {
                 let (tx, _) = watch::channel(None);
                 state.result_tx = tx;
                 state.running = true;
+                record_capacity_refresh_inflight(1);
                 true
             }
         };
@@ -643,6 +834,7 @@ impl HybridCapacityManager {
         }
 
         tokio::spawn(async move {
+            let refresh_start = Instant::now();
             let result = AssertUnwindSafe(refresh_fn()).catch_unwind().await.unwrap_or_else(|err| {
                 warn!(error = ?err, "capacity refresh function panicked");
                 Err("capacity refresh panicked".to_string())
@@ -650,9 +842,19 @@ impl HybridCapacityManager {
             if let Ok(update) = &result {
                 self.update_capacity(update.clone(), source).await;
             }
+            let refresh_duration = refresh_start.elapsed();
+            if result.is_err() {
+                record_capacity_update_failed(source.as_metric_label());
+            }
+            record_capacity_refresh_result(
+                source.as_metric_label(),
+                if result.is_ok() { "success" } else { "error" },
+                refresh_duration,
+            );
 
             let mut state = self.refresh_state.lock().await;
             state.running = false;
+            record_capacity_refresh_inflight(0);
             let _ = state.result_tx.send(Some(result));
         });
 
@@ -670,7 +872,6 @@ impl HybridCapacityManager {
     }
 
     /// Return whether a refresh is currently in flight.
-    #[cfg(test)]
     pub async fn refresh_in_progress(&self) -> bool {
         self.refresh_state.lock().await.running
     }
@@ -692,20 +893,19 @@ pub fn get_capacity_manager() -> Arc<HybridCapacityManager> {
 /// without affecting the global singleton, avoiding test pollution.
 ///
 /// # Example
-/// ```no_run
+/// ```ignore
 /// let manager = create_isolated_manager(HybridStrategyConfig::default());
 /// manager
 ///     .update_capacity(CapacityUpdate::exact(1000, 0), DataSource::RealTime)
 ///     .await;
 /// ```
-#[cfg(test)]
 #[allow(dead_code)]
 pub fn create_isolated_manager(config: HybridStrategyConfig) -> Arc<HybridCapacityManager> {
     Arc::new(HybridCapacityManager::new(config))
 }
 
 /// Start background update task
-pub async fn start_background_task(disks: Vec<rustfs_madmin::Disk>) {
+pub async fn start_background_task(disks: Vec<CapacityDiskRef>) {
     let manager = get_capacity_manager();
     let mut interval = manager.get_config().scheduled_update_interval;
 
@@ -727,12 +927,10 @@ pub async fn start_background_task(disks: Vec<rustfs_madmin::Disk>) {
             let disks = disks.clone();
             let started = manager
                 .clone()
-                .spawn_refresh_if_needed(DataSource::Scheduled, move || async move {
-                    calculate_data_dir_used_capacity(&disks)
-                        .await
-                        .map(|scan| scan.to_capacity_update())
-                        .map_err(|e| e.to_string())
-                })
+                .spawn_refresh_if_needed(
+                    DataSource::Scheduled,
+                    move || async move { refresh_capacity_with_scope(disks, false).await },
+                )
                 .await;
 
             if started {
@@ -751,11 +949,14 @@ pub async fn start_background_task(disks: Vec<rustfs_madmin::Disk>) {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use rustfs_common::capacity_scope::{CapacityScope, CapacityScopeDisk, record_capacity_scope, record_global_dirty_scope};
     use rustfs_config::{
         ENV_CAPACITY_FAST_UPDATE_THRESHOLD, ENV_CAPACITY_MAX_FILES_THRESHOLD, ENV_CAPACITY_SAMPLE_RATE,
         ENV_CAPACITY_STAT_TIMEOUT, ENV_CAPACITY_WRITE_FREQUENCY_THRESHOLD, ENV_CAPACITY_WRITE_TRIGGER_DELAY,
     };
     use serial_test::serial;
+    use std::sync::Arc;
+    use std::sync::atomic::{AtomicUsize, Ordering};
 
     #[test]
     #[serial]
@@ -892,6 +1093,22 @@ mod tests {
         assert_eq!(cached.unwrap().total_used, 1000);
     }
 
+    #[tokio::test]
+    #[serial]
+    async fn test_update_capacity_preserves_retrieval_metadata() {
+        let manager = HybridCapacityManager::from_env();
+
+        manager
+            .update_capacity(CapacityUpdate::exact(1000, 10), DataSource::RealTime)
+            .await;
+
+        let cached = manager.get_capacity().await.unwrap();
+        assert_eq!(cached.total_used, 1000);
+        assert_eq!(cached.file_count, 10);
+        assert_eq!(cached.source, DataSource::RealTime);
+        assert!(!cached.is_estimated);
+    }
+
     #[tokio::test]
     #[serial]
     async fn test_record_write_operation() {
@@ -903,6 +1120,18 @@ mod tests {
         assert_eq!(frequency, 1);
     }
 
+    #[tokio::test]
+    #[serial]
+    async fn test_write_frequency_window() {
+        let manager = HybridCapacityManager::from_env();
+
+        for _ in 0..20 {
+            manager.record_write_operation().await;
+        }
+
+        assert_eq!(manager.get_write_frequency().await, 20);
+    }
+
     #[tokio::test]
     #[serial]
     async fn test_needs_fast_update() {
@@ -920,6 +1149,326 @@ mod tests {
         assert!(!manager.needs_fast_update().await);
     }
 
+    #[tokio::test]
+    #[serial]
+    async fn test_cache_age_tracking() {
+        let manager = HybridCapacityManager::from_env();
+
+        assert!(manager.get_cache_age().await.is_none());
+
+        manager
+            .update_capacity(CapacityUpdate::exact(1000, 1), DataSource::RealTime)
+            .await;
+
+        let age = manager.get_cache_age().await.unwrap();
+        assert!(age < Duration::from_secs(1));
+
+        tokio::time::sleep(Duration::from_millis(100)).await;
+
+        let age = manager.get_cache_age().await.unwrap();
+        assert!(age >= Duration::from_millis(100));
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_data_source_tracking() {
+        let manager = HybridCapacityManager::from_env();
+
+        for source in [
+            DataSource::RealTime,
+            DataSource::Scheduled,
+            DataSource::WriteTriggered,
+            DataSource::Fallback,
+        ] {
+            manager.update_capacity(CapacityUpdate::exact(1000, 1), source).await;
+            assert_eq!(manager.get_capacity().await.unwrap().source, source);
+        }
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_needs_fast_update_waits_for_write_trigger_delay() {
+        let manager = create_isolated_manager(HybridStrategyConfig {
+            scheduled_update_interval: Duration::from_secs(60),
+            write_trigger_delay: Duration::from_millis(50),
+            write_frequency_threshold: 1,
+            fast_update_threshold: Duration::from_millis(10),
+            enable_smart_update: true,
+            enable_write_trigger: true,
+        });
+
+        manager
+            .update_capacity(CapacityUpdate::exact(1000, 0), DataSource::RealTime)
+            .await;
+        tokio::time::sleep(Duration::from_millis(15)).await;
+
+        manager.record_write_operation().await;
+        manager.record_write_operation().await;
+        tokio::time::sleep(Duration::from_millis(5)).await;
+
+        assert!(
+            !manager.needs_fast_update().await,
+            "write-triggered refresh should wait for debounce delay after a qualifying burst"
+        );
+
+        tokio::time::sleep(Duration::from_millis(60)).await;
+        assert!(manager.needs_fast_update().await);
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_needs_fast_update_respects_enable_write_trigger() {
+        let manager = create_isolated_manager(HybridStrategyConfig {
+            scheduled_update_interval: Duration::from_secs(60),
+            write_trigger_delay: Duration::from_secs(60),
+            write_frequency_threshold: 1,
+            fast_update_threshold: Duration::from_millis(10),
+            enable_smart_update: true,
+            enable_write_trigger: false,
+        });
+
+        manager
+            .update_capacity(CapacityUpdate::exact(1000, 0), DataSource::RealTime)
+            .await;
+        tokio::time::sleep(Duration::from_millis(15)).await;
+
+        manager.record_write_operation().await;
+        manager.record_write_operation().await;
+
+        assert!(
+            !manager.needs_fast_update().await,
+            "write-triggered refresh should be disabled when enable_write_trigger is false"
+        );
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_concurrent_access() {
+        let manager = Arc::new(HybridCapacityManager::from_env());
+        let mut handles = Vec::new();
+
+        for i in 0..10 {
+            let mgr = manager.clone();
+            handles.push(tokio::spawn(async move {
+                mgr.update_capacity(CapacityUpdate::exact(i as u64 * 100, i), DataSource::RealTime)
+                    .await;
+                mgr.record_write_operation().await;
+            }));
+        }
+
+        for handle in handles {
+            handle.await.unwrap();
+        }
+
+        assert!(manager.get_capacity().await.is_some());
+        assert_eq!(manager.get_write_frequency().await, 10);
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_performance_overhead() {
+        let manager = Arc::new(HybridCapacityManager::from_env());
+        let start = Instant::now();
+
+        for i in 0..1000 {
+            manager
+                .update_capacity(CapacityUpdate::exact(i as u64, i), DataSource::RealTime)
+                .await;
+            manager.record_write_operation().await;
+            let _ = manager.get_capacity().await;
+        }
+
+        assert!(start.elapsed() < Duration::from_secs(1));
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_refresh_or_join_singleflight() {
+        let manager = Arc::new(HybridCapacityManager::from_env());
+        let calls = Arc::new(AtomicUsize::new(0));
+
+        let mgr1 = manager.clone();
+        let calls1 = calls.clone();
+        let first = tokio::spawn(async move {
+            mgr1.refresh_or_join(DataSource::Scheduled, move || async move {
+                calls1.fetch_add(1, Ordering::SeqCst);
+                tokio::time::sleep(Duration::from_millis(50)).await;
+                Ok(CapacityUpdate::exact(2048, 8))
+            })
+            .await
+        });
+
+        tokio::time::sleep(Duration::from_millis(10)).await;
+
+        let mgr2 = manager.clone();
+        let calls2 = calls.clone();
+        let second = tokio::spawn(async move {
+            mgr2.refresh_or_join(DataSource::WriteTriggered, move || async move {
+                calls2.fetch_add(1, Ordering::SeqCst);
+                Ok(CapacityUpdate::exact(4096, 16))
+            })
+            .await
+        });
+
+        let first = first.await.unwrap().unwrap();
+        let second = second.await.unwrap().unwrap();
+
+        assert_eq!(calls.load(Ordering::SeqCst), 1);
+        assert_eq!(first.total_used, 2048);
+        assert_eq!(second.total_used, 2048);
+        let cached = manager.get_capacity().await.unwrap();
+        assert_eq!(cached.total_used, 2048);
+        assert_eq!(cached.file_count, 8);
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_spawn_refresh_if_needed_deduplicates_background_refresh() {
+        let manager = Arc::new(HybridCapacityManager::from_env());
+        let calls = Arc::new(AtomicUsize::new(0));
+
+        let first_manager = manager.clone();
+        let first_calls = calls.clone();
+        let started = first_manager
+            .clone()
+            .spawn_refresh_if_needed(DataSource::Scheduled, move || async move {
+                first_calls.fetch_add(1, Ordering::SeqCst);
+                tokio::time::sleep(Duration::from_millis(50)).await;
+                Ok(CapacityUpdate::estimated(8192, 32))
+            })
+            .await;
+        assert!(started);
+
+        let second_manager = manager.clone();
+        let second_calls = calls.clone();
+        let started = second_manager
+            .clone()
+            .spawn_refresh_if_needed(DataSource::Scheduled, move || async move {
+                second_calls.fetch_add(1, Ordering::SeqCst);
+                Ok(CapacityUpdate::exact(1, 1))
+            })
+            .await;
+        assert!(!started);
+
+        tokio::time::sleep(Duration::from_millis(100)).await;
+
+        assert_eq!(calls.load(Ordering::SeqCst), 1);
+        assert!(!manager.refresh_in_progress().await);
+        let cached = manager.get_capacity().await.unwrap();
+        assert_eq!(cached.total_used, 8192);
+        assert!(cached.is_estimated);
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_record_write_operation_with_scope_token_marks_dirty_disks() {
+        let manager = create_isolated_manager(HybridStrategyConfig::default());
+        let token = uuid::Uuid::new_v4();
+        record_capacity_scope(
+            token,
+            CapacityScope {
+                disks: vec![CapacityScopeDisk {
+                    endpoint: "node-a".to_string(),
+                    drive_path: "/tmp/disk-a".to_string(),
+                }],
+            },
+        );
+
+        manager.record_write_operation_with_scope_token(Some(token)).await;
+
+        let dirty_disks = manager.get_dirty_disks().await;
+        assert_eq!(dirty_disks.len(), 1);
+        assert_eq!(dirty_disks[0].endpoint, "node-a");
+        assert_eq!(dirty_disks[0].drive_path, "/tmp/disk-a");
+        assert_eq!(manager.get_write_frequency().await, 1);
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_get_dirty_disks_drains_global_dirty_scope_registry() {
+        let manager = create_isolated_manager(HybridStrategyConfig::default());
+        record_global_dirty_scope(CapacityScope {
+            disks: vec![CapacityScopeDisk {
+                endpoint: "node-bg".to_string(),
+                drive_path: "/tmp/disk-bg".to_string(),
+            }],
+        });
+
+        let dirty_disks = manager.get_dirty_disks().await;
+        assert_eq!(dirty_disks.len(), 1);
+        assert_eq!(dirty_disks[0].endpoint, "node-bg");
+        assert_eq!(dirty_disks[0].drive_path, "/tmp/disk-bg");
+
+        let second_read = manager.get_dirty_disks().await;
+        assert_eq!(second_read.len(), 1);
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_update_capacity_recomputes_total_from_disk_cache_for_subset_refresh() {
+        let manager = create_isolated_manager(HybridStrategyConfig::default());
+
+        manager
+            .update_capacity(
+                CapacityUpdate {
+                    total_used: 300,
+                    file_count: 3,
+                    is_estimated: false,
+                    per_disk: vec![
+                        DiskCapacityUpdate {
+                            disk: CapacityScopeDisk {
+                                endpoint: "node-a".to_string(),
+                                drive_path: "/tmp/disk-a".to_string(),
+                            },
+                            used_bytes: 100,
+                            file_count: 1,
+                            is_estimated: false,
+                        },
+                        DiskCapacityUpdate {
+                            disk: CapacityScopeDisk {
+                                endpoint: "node-b".to_string(),
+                                drive_path: "/tmp/disk-b".to_string(),
+                            },
+                            used_bytes: 200,
+                            file_count: 2,
+                            is_estimated: false,
+                        },
+                    ],
+                    expected_disk_count: Some(2),
+                    replaces_disk_cache: true,
+                    clear_dirty_disks: Vec::new(),
+                },
+                DataSource::RealTime,
+            )
+            .await;
+
+        manager
+            .update_capacity(
+                CapacityUpdate {
+                    total_used: 150,
+                    file_count: 1,
+                    is_estimated: false,
+                    per_disk: vec![DiskCapacityUpdate {
+                        disk: CapacityScopeDisk {
+                            endpoint: "node-a".to_string(),
+                            drive_path: "/tmp/disk-a".to_string(),
+                        },
+                        used_bytes: 150,
+                        file_count: 1,
+                        is_estimated: false,
+                    }],
+                    expected_disk_count: Some(1),
+                    replaces_disk_cache: false,
+                    clear_dirty_disks: Vec::new(),
+                },
+                DataSource::WriteTriggered,
+            )
+            .await;
+
+        let cached = manager.get_capacity().await.unwrap();
+        assert_eq!(cached.total_used, 350);
+    }
+
     #[tokio::test]
     #[serial]
     async fn test_config_from_env() {
diff --git a/crates/object-capacity/src/lib.rs b/crates/object-capacity/src/lib.rs
new file mode 100644
index 000000000..c5730cdbf
--- /dev/null
+++ b/crates/object-capacity/src/lib.rs
@@ -0,0 +1,20 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+pub mod capacity_manager;
+pub mod scan;
+pub mod types;
+
+pub use scan::scan_used_capacity_disks;
+pub use types::{CapacityDiskRef, CapacityScanSummary};
diff --git a/crates/object-capacity/src/scan.rs b/crates/object-capacity/src/scan.rs
new file mode 100644
index 000000000..9fab908ab
--- /dev/null
+++ b/crates/object-capacity/src/scan.rs
@@ -0,0 +1,903 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use super::capacity_manager::{
+    CapacityUpdate, DiskCapacityUpdate, HybridCapacityManager, get_enable_dynamic_timeout, get_follow_symlinks,
+    get_max_files_threshold, get_max_symlink_depth, get_max_timeout, get_min_timeout, get_sample_rate, get_stall_timeout,
+    get_stat_timeout,
+};
+use super::types::{CapacityDiskRef, CapacityScanResult, CapacityScanSummary};
+use futures::{StreamExt, stream};
+use rustfs_common::capacity_scope::CapacityScopeDisk;
+use rustfs_io_metrics::capacity_metrics::{
+    record_capacity_dynamic_timeout, record_capacity_scan_disk, record_capacity_scan_mode, record_capacity_scan_sampling,
+    record_capacity_stall_detected, record_capacity_symlink, record_capacity_timeout_fallback,
+};
+use std::collections::HashSet;
+use std::path::{Path, PathBuf};
+use std::time::{Duration, Instant};
+use tracing::{debug, info, warn};
+use walkdir::WalkDir;
+
+const MAX_CAPACITY_SCAN_CONCURRENCY: usize = 4;
+const CAPACITY_PROGRESS_CHECK_STRIDE: usize = 512;
+
+#[derive(Debug)]
+struct DiskScanOutcome {
+    disk_label: String,
+    drive_path: String,
+    duration: Duration,
+    result: Result<CapacityScanResult, std::io::Error>,
+}
+
+#[derive(Debug, Clone)]
+struct DiskCapacityScanResult {
+    disk: CapacityScopeDisk,
+    scan: CapacityScanResult,
+}
+
+#[derive(Debug, Clone)]
+struct CapacityScanReport {
+    summary: CapacityScanResult,
+    per_disk: Vec<DiskCapacityScanResult>,
+}
+
+impl CapacityScanReport {
+    fn into_capacity_update(self, expected_disk_count: usize, replaces_disk_cache: bool) -> CapacityUpdate {
+        let mut update = if self.summary.is_estimated {
+            CapacityUpdate::estimated(self.summary.used_bytes, self.summary.file_count)
+        } else {
+            CapacityUpdate::exact(self.summary.used_bytes, self.summary.file_count)
+        };
+
+        if !self.summary.had_partial_errors && self.per_disk.len() == expected_disk_count {
+            update.per_disk = self
+                .per_disk
+                .into_iter()
+                .map(|entry| DiskCapacityUpdate {
+                    disk: entry.disk,
+                    used_bytes: entry.scan.used_bytes,
+                    file_count: entry.scan.file_count,
+                    is_estimated: entry.scan.is_estimated,
+                })
+                .collect();
+            update.expected_disk_count = Some(expected_disk_count);
+            update.replaces_disk_cache = replaces_disk_cache;
+            update.clear_dirty_disks = update.per_disk.iter().map(|entry| entry.disk.clone()).collect();
+        }
+
+        update
+    }
+}
+
+fn disk_metric_label(disk: &CapacityDiskRef) -> String {
+    let mount_name = Path::new(&disk.drive_path)
+        .file_name()
+        .and_then(|value| value.to_str())
+        .filter(|value| !value.is_empty())
+        .unwrap_or(disk.drive_path.as_str());
+    format!("{}:{mount_name}", disk.endpoint)
+}
+
+fn disk_scope_key(disk: &CapacityDiskRef) -> CapacityScopeDisk {
+    CapacityScopeDisk {
+        endpoint: disk.endpoint.clone(),
+        drive_path: disk.drive_path.clone(),
+    }
+}
+
+async fn scan_disk_used_capacity(disk: CapacityDiskRef) -> DiskScanOutcome {
+    let disk_label = disk_metric_label(&disk);
+    let drive_path = disk.drive_path.clone();
+    let start = Instant::now();
+    let result = get_dir_size_async(Path::new(&drive_path)).await;
+
+    DiskScanOutcome {
+        disk_label,
+        drive_path,
+        duration: start.elapsed(),
+        result,
+    }
+}
+
+async fn calculate_data_dir_used_capacity_report(
+    disks: &[CapacityDiskRef],
+) -> Result<CapacityScanReport, Box<dyn std::error::Error + Send + Sync>> {
+    let start = Instant::now();
+    let mut total_used = 0u64;
+    let mut total_files = 0usize;
+    let mut total_sampled = 0usize;
+    let mut has_failure = false;
+    let mut has_success = false;
+    let mut is_estimated = false;
+    let mut per_disk = Vec::with_capacity(disks.len());
+
+    let concurrency_limit = disks.len().clamp(1, MAX_CAPACITY_SCAN_CONCURRENCY);
+    let mut scans = stream::iter(disks.iter().cloned().map(scan_disk_used_capacity)).buffer_unordered(concurrency_limit);
+
+    while let Some(outcome) = scans.next().await {
+        match outcome.result {
+            Ok(scan) => {
+                record_capacity_scan_disk(
+                    outcome.disk_label.as_str(),
+                    outcome.duration,
+                    scan.file_count,
+                    scan.sampled_count,
+                    scan.is_estimated,
+                    scan.had_partial_errors,
+                );
+                debug!(
+                    "Data directory {} size: {} bytes, files={}, sampled={}, estimated={}, duration={:?}",
+                    outcome.drive_path, scan.used_bytes, scan.file_count, scan.sampled_count, scan.is_estimated, outcome.duration
+                );
+                total_used += scan.used_bytes;
+                total_files += scan.file_count;
+                total_sampled += scan.sampled_count;
+                is_estimated |= scan.is_estimated;
+                has_failure |= scan.had_partial_errors;
+                has_success = true;
+                if let Some(disk) = disks
+                    .iter()
+                    .find(|disk| disk.drive_path == outcome.drive_path && disk_metric_label(disk) == outcome.disk_label)
+                {
+                    per_disk.push(DiskCapacityScanResult {
+                        disk: disk_scope_key(disk),
+                        scan,
+                    });
+                }
+            }
+            Err(e) => {
+                record_capacity_scan_disk(outcome.disk_label.as_str(), outcome.duration, 0, 0, false, true);
+                warn!("Failed to get size for directory {}: {:?}", outcome.drive_path, e);
+                has_failure = true;
+            }
+        }
+    }
+
+    if !has_success {
+        return Err("All directories failed to calculate size".into());
+    }
+
+    if has_failure {
+        warn!("Some directories failed to calculate size, result may be incomplete");
+    }
+
+    let mut summary = CapacityScanResult {
+        used_bytes: total_used,
+        file_count: total_files,
+        sampled_count: total_sampled,
+        is_estimated,
+        scan_duration: start.elapsed(),
+        had_partial_errors: false,
+    };
+
+    if has_failure {
+        summary = summary.with_partial_errors();
+    }
+
+    Ok(CapacityScanReport { summary, per_disk })
+}
+
+/// Calculate actual used capacity of all data directories.
+pub(crate) async fn calculate_data_dir_used_capacity(
+    disks: &[CapacityDiskRef],
+) -> Result<CapacityScanResult, Box<dyn std::error::Error + Send + Sync>> {
+    Ok(calculate_data_dir_used_capacity_report(disks).await?.summary)
+}
+
+pub async fn select_capacity_refresh_disks(
+    capacity_manager: &HybridCapacityManager,
+    disks: &[CapacityDiskRef],
+) -> (Vec<CapacityDiskRef>, bool) {
+    if !capacity_manager.can_refresh_dirty_subset().await {
+        return (disks.to_vec(), false);
+    }
+
+    let dirty_disks = capacity_manager.get_dirty_disks().await;
+    if dirty_disks.is_empty() {
+        return (disks.to_vec(), false);
+    }
+
+    let dirty_set: HashSet<CapacityScopeDisk> = dirty_disks.into_iter().collect();
+    let selected: Vec<_> = disks
+        .iter()
+        .filter(|disk| dirty_set.contains(&disk_scope_key(disk)))
+        .cloned()
+        .collect();
+
+    if selected.is_empty() || selected.len() >= disks.len() {
+        (disks.to_vec(), false)
+    } else {
+        (selected, true)
+    }
+}
+
+pub async fn refresh_capacity_with_scope(disks: Vec<CapacityDiskRef>, dirty_subset: bool) -> Result<CapacityUpdate, String> {
+    let report = calculate_data_dir_used_capacity_report(&disks)
+        .await
+        .map_err(|e| e.to_string())?;
+
+    if dirty_subset && report.summary.had_partial_errors {
+        return Err("dirty subset refresh had partial errors".to_string());
+    }
+
+    Ok(report.into_capacity_update(disks.len(), !dirty_subset))
+}
+
+/// Scan the provided local disk roots and return a summarized used-capacity result.
+///
+/// This is primarily intended for benchmarks and operational tooling that need to exercise
+/// the same scan path as admin capacity queries without going through the full admin stack.
+pub async fn scan_used_capacity_disks(
+    disks: &[CapacityDiskRef],
+) -> Result<CapacityScanSummary, Box<dyn std::error::Error + Send + Sync>> {
+    Ok(calculate_data_dir_used_capacity(disks).await?.into())
+}
+
+/// Tracker for symlink resolution with circular reference detection.
+struct SymlinkTracker {
+    visited: HashSet<PathBuf>,
+    symlink_count: usize,
+    symlink_size: u64,
+    max_depth: u8,
+}
+
+impl SymlinkTracker {
+    fn new(max_depth: u8) -> Self {
+        Self {
+            visited: HashSet::new(),
+            symlink_count: 0,
+            symlink_size: 0,
+            max_depth,
+        }
+    }
+
+    fn should_follow(&self, path: &Path, depth: u8) -> bool {
+        if depth >= self.max_depth {
+            debug!("Symlink depth limit reached: {} >= {}, not following {:?}", depth, self.max_depth, path);
+            return false;
+        }
+
+        if self.visited.contains(path) {
+            warn!("Circular symlink reference detected: {:?}, skipping", path);
+            return false;
+        }
+
+        true
+    }
+
+    fn record_symlink(&mut self, path: PathBuf, size: u64) {
+        if self.visited.insert(path) {
+            self.symlink_count += 1;
+            self.symlink_size += size;
+            record_capacity_symlink(size);
+        }
+    }
+
+    fn get_stats(&self) -> (usize, u64) {
+        (self.symlink_count, self.symlink_size)
+    }
+}
+
+/// Monitor for directory traversal progress with timeout and stall detection.
+struct ProgressMonitor {
+    start_time: Instant,
+    last_check: Instant,
+    last_checkpoint_files: usize,
+    timeout: Duration,
+    min_timeout: Duration,
+    max_timeout: Duration,
+    stall_timeout: Duration,
+    enable_dynamic_timeout: bool,
+    used_dynamic_timeout: bool,
+}
+
+impl ProgressMonitor {
+    fn new(
+        base_timeout: Duration,
+        min_timeout: Duration,
+        max_timeout: Duration,
+        stall_timeout: Duration,
+        enable_dynamic: bool,
+    ) -> Self {
+        Self {
+            start_time: Instant::now(),
+            last_check: Instant::now(),
+            last_checkpoint_files: 0,
+            timeout: base_timeout,
+            min_timeout,
+            max_timeout,
+            stall_timeout,
+            enable_dynamic_timeout: enable_dynamic,
+            used_dynamic_timeout: false,
+        }
+    }
+
+    fn calculate_dynamic_timeout(&mut self, file_count: usize, avg_file_size: u64) -> Duration {
+        if !self.enable_dynamic_timeout {
+            return self.timeout;
+        }
+
+        self.used_dynamic_timeout = true;
+
+        let file_factor = (file_count as f64).sqrt() * 0.01;
+        let size_factor = if avg_file_size > 0 {
+            (avg_file_size as f64).log(10.0) * 0.05
+        } else {
+            0.0
+        };
+
+        let multiplier = 1.0 + file_factor + size_factor;
+        let adjusted_timeout = self.timeout.mul_f64(multiplier.min(5.0));
+        let clamped_timeout = adjusted_timeout.max(self.min_timeout).min(self.max_timeout);
+
+        debug!(
+            "Dynamic timeout calculation: files={}, avg_size={}, multiplier={:.2}, base_timeout={:?}, adjusted_timeout={:?}, clamped_timeout={:?}",
+            file_count, avg_file_size, multiplier, self.timeout, adjusted_timeout, clamped_timeout
+        );
+
+        clamped_timeout
+    }
+
+    fn update_and_check_timeout(&mut self, files_processed: usize, avg_file_size: u64) -> Result<(), std::io::Error> {
+        let elapsed = self.start_time.elapsed();
+        let dynamic_timeout = if self.enable_dynamic_timeout {
+            self.calculate_dynamic_timeout(files_processed, avg_file_size)
+        } else {
+            self.timeout
+        };
+
+        if elapsed >= dynamic_timeout {
+            warn!(
+                "Directory size calculation timeout after {} files, elapsed: {:?}, timeout: {:?}",
+                files_processed, elapsed, dynamic_timeout
+            );
+
+            if self.enable_dynamic_timeout {
+                record_capacity_dynamic_timeout(dynamic_timeout);
+            }
+
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::TimedOut,
+                format!("Timeout after {} files", files_processed),
+            ));
+        }
+
+        let now = Instant::now();
+        if now.duration_since(self.last_check) >= self.stall_timeout {
+            let files_per_checkpoint = files_processed.saturating_sub(self.last_checkpoint_files);
+
+            if files_per_checkpoint == 0 && files_processed > 0 {
+                warn!(
+                    "No progress detected for {:?}, possible stall at {} files",
+                    self.stall_timeout, files_processed
+                );
+
+                record_capacity_stall_detected();
+
+                return Err(std::io::Error::new(
+                    std::io::ErrorKind::TimedOut,
+                    format!("Stall detected at {} files", files_processed),
+                ));
+            }
+
+            self.last_check = now;
+            self.last_checkpoint_files = files_processed;
+        }
+
+        Ok(())
+    }
+
+    fn record_timeout_fallback(&self) {
+        record_capacity_timeout_fallback();
+    }
+}
+
+async fn get_dir_size_async(path: &Path) -> Result<CapacityScanResult, std::io::Error> {
+    let path = path.to_path_buf();
+
+    let max_files_threshold = get_max_files_threshold();
+    let base_timeout = get_stat_timeout();
+    let min_timeout = get_min_timeout();
+    let max_timeout = get_max_timeout();
+    let stall_timeout = get_stall_timeout();
+    let sample_rate = get_sample_rate();
+    let enable_dynamic_timeout = get_enable_dynamic_timeout();
+    let follow_symlinks = get_follow_symlinks();
+    let max_symlink_depth = get_max_symlink_depth();
+
+    let effective_sample_rate = if sample_rate == 0 {
+        warn!("Invalid sampling configuration: sample_rate=0. Clamping to 1 to avoid panic.");
+        1
+    } else {
+        sample_rate
+    };
+
+    tokio::task::spawn_blocking(move || {
+        if !path.exists() {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::NotFound,
+                format!("Directory not found: {:?}", path),
+            ));
+        }
+
+        let start_time = Instant::now();
+        let mut exact_prefix_bytes = 0u64;
+        let mut overflow_sampled_bytes = 0u64;
+        let mut file_count = 0usize;
+        let mut sampled_count = 0usize;
+        let mut had_partial_errors = false;
+        let mut last_progress_check_files = 0usize;
+
+        let mut symlink_tracker = SymlinkTracker::new(max_symlink_depth);
+        let mut progress_monitor =
+            ProgressMonitor::new(base_timeout, min_timeout, max_timeout, stall_timeout, enable_dynamic_timeout);
+
+        let walker = WalkDir::new(&path)
+            .follow_links(follow_symlinks)
+            .follow_root_links(follow_symlinks)
+            .into_iter();
+
+        for entry_result in walker {
+            let entry = match entry_result {
+                Ok(entry) => entry,
+                Err(err) => {
+                    warn!("Failed to traverse directory entry under {:?}: {}", path, err);
+                    had_partial_errors = true;
+                    continue;
+                }
+            };
+
+            if follow_symlinks
+                && entry.path_is_symlink()
+                && let Ok(target) = std::fs::read_link(entry.path())
+                && symlink_tracker.should_follow(&target, entry.depth().min(u8::MAX as usize) as u8)
+            {
+                symlink_tracker.record_symlink(target, 0);
+            }
+
+            let file_type = entry.file_type();
+            if file_type.is_dir() {
+                continue;
+            }
+
+            if file_type.is_symlink() || !file_type.is_file() {
+                continue;
+            }
+
+            let metadata = match entry.metadata() {
+                Ok(meta) => meta,
+                Err(err) => {
+                    warn!("Failed to get metadata for {:?}: {}", entry.path(), err);
+                    had_partial_errors = true;
+                    continue;
+                }
+            };
+
+            file_count += 1;
+            let exact_count = file_count.min(max_files_threshold);
+            let avg_size = if exact_count > 0 {
+                exact_prefix_bytes / exact_count as u64
+            } else {
+                0
+            };
+
+            let should_check_progress =
+                file_count == 1 || file_count.saturating_sub(last_progress_check_files) >= CAPACITY_PROGRESS_CHECK_STRIDE;
+
+            if should_check_progress && let Err(e) = progress_monitor.update_and_check_timeout(file_count, avg_size) {
+                if sampled_count > 0 {
+                    let overflow_count = file_count.saturating_sub(max_files_threshold);
+                    let estimated_overflow = overflow_sampled_bytes.saturating_mul(overflow_count as u64) / sampled_count as u64;
+                    let estimated_total = exact_prefix_bytes.saturating_add(estimated_overflow);
+                    info!(
+                        "Timeout/stall at {} files, using sampled estimate: exact_prefix={} overflow_estimate={} sampled={}",
+                        file_count, exact_prefix_bytes, estimated_overflow, sampled_count
+                    );
+                    progress_monitor.record_timeout_fallback();
+                    record_capacity_scan_sampling(sampled_count, true);
+                    record_capacity_scan_mode("timeout_fallback");
+                    return Ok(CapacityScanResult {
+                        used_bytes: estimated_total,
+                        file_count,
+                        sampled_count,
+                        is_estimated: true,
+                        scan_duration: start_time.elapsed(),
+                        had_partial_errors,
+                    });
+                }
+                return Err(e);
+            }
+            if should_check_progress {
+                last_progress_check_files = file_count;
+            }
+
+            if file_count <= max_files_threshold {
+                exact_prefix_bytes += metadata.len();
+            } else {
+                let overflow_index = file_count - max_files_threshold;
+                if overflow_index.is_multiple_of(effective_sample_rate) {
+                    overflow_sampled_bytes += metadata.len();
+                    sampled_count += 1;
+                }
+
+                if file_count.is_multiple_of(100_000) {
+                    debug!(
+                        "Processed {} files, exact_prefix_bytes={}, sampled_overflow={} files/{} bytes",
+                        file_count, exact_prefix_bytes, sampled_count, overflow_sampled_bytes
+                    );
+                }
+            }
+        }
+
+        if file_count > last_progress_check_files {
+            let exact_count = file_count.min(max_files_threshold);
+            let avg_size = if exact_count > 0 {
+                exact_prefix_bytes / exact_count as u64
+            } else {
+                0
+            };
+
+            if let Err(e) = progress_monitor.update_and_check_timeout(file_count, avg_size) {
+                if sampled_count > 0 {
+                    let overflow_count = file_count.saturating_sub(max_files_threshold);
+                    let estimated_overflow = overflow_sampled_bytes.saturating_mul(overflow_count as u64) / sampled_count as u64;
+                    let estimated_total = exact_prefix_bytes.saturating_add(estimated_overflow);
+                    info!(
+                        "Timeout/stall at {} files during final check, using sampled estimate: exact_prefix={} overflow_estimate={} sampled={}",
+                        file_count, exact_prefix_bytes, estimated_overflow, sampled_count
+                    );
+                    progress_monitor.record_timeout_fallback();
+                    record_capacity_scan_sampling(sampled_count, true);
+                    record_capacity_scan_mode("timeout_fallback");
+                    return Ok(CapacityScanResult {
+                        used_bytes: estimated_total,
+                        file_count,
+                        sampled_count,
+                        is_estimated: true,
+                        scan_duration: start_time.elapsed(),
+                        had_partial_errors,
+                    });
+                }
+                return Err(e);
+            }
+        }
+
+        let (symlink_count, symlink_size) = symlink_tracker.get_stats();
+        if symlink_count > 0 {
+            info!(
+                "Symlink tracking: {} symlinks processed, total tracked size: {} bytes",
+                symlink_count, symlink_size
+            );
+        }
+
+        if file_count > max_files_threshold && sampled_count > 0 {
+            let overflow_count = file_count - max_files_threshold;
+            let estimated_overflow = overflow_sampled_bytes.saturating_mul(overflow_count as u64) / sampled_count as u64;
+            let estimated_size = exact_prefix_bytes.saturating_add(estimated_overflow);
+            info!(
+                "Large directory detected: {} files, estimated size: {} bytes (exact prefix: {}, sampled overflow {}/{})",
+                file_count, estimated_size, exact_prefix_bytes, sampled_count, overflow_count
+            );
+            record_capacity_scan_sampling(sampled_count, true);
+            record_capacity_scan_mode("estimated");
+            Ok(CapacityScanResult {
+                used_bytes: estimated_size,
+                file_count,
+                sampled_count,
+                is_estimated: true,
+                scan_duration: start_time.elapsed(),
+                had_partial_errors,
+            })
+        } else if file_count > max_files_threshold {
+            let overflow_count = file_count - max_files_threshold;
+            let exact_prefix_count = file_count.min(max_files_threshold) as u64;
+            let avg_prefix_size = if exact_prefix_count > 0 {
+                exact_prefix_bytes / exact_prefix_count
+            } else {
+                0
+            };
+            let estimated_overflow = avg_prefix_size.saturating_mul(overflow_count as u64);
+            let estimated_size = exact_prefix_bytes.saturating_add(estimated_overflow);
+            info!(
+                "Large directory detected: {} files, estimated size: {} bytes (no overflow samples, used prefix average {} bytes/file)",
+                file_count, estimated_size, avg_prefix_size
+            );
+            record_capacity_scan_sampling(0, true);
+            record_capacity_scan_mode("estimated");
+            Ok(CapacityScanResult {
+                used_bytes: estimated_size,
+                file_count,
+                sampled_count: 0,
+                is_estimated: true,
+                scan_duration: start_time.elapsed(),
+                had_partial_errors,
+            })
+        } else {
+            record_capacity_scan_sampling(0, false);
+            debug!(
+                "Directory size calculation completed: {} files, {} bytes, took {:?}",
+                file_count,
+                exact_prefix_bytes,
+                start_time.elapsed()
+            );
+            record_capacity_scan_mode("exact");
+            Ok(CapacityScanResult {
+                used_bytes: exact_prefix_bytes,
+                file_count,
+                sampled_count,
+                is_estimated: false,
+                scan_duration: start_time.elapsed(),
+                had_partial_errors,
+            })
+        }
+    })
+    .await
+    .map_err(std::io::Error::other)?
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::capacity_manager::{DataSource, HybridStrategyConfig, create_isolated_manager};
+    use rustfs_common::capacity_scope::{CapacityScope, CapacityScopeDisk};
+    use rustfs_config::ENV_CAPACITY_FOLLOW_SYMLINKS;
+    use serial_test::serial;
+
+    #[tokio::test]
+    async fn test_get_dir_size_async_empty_directory() {
+        use tempfile::TempDir;
+
+        let temp_dir = TempDir::new().unwrap();
+        let size = get_dir_size_async(temp_dir.path()).await.unwrap();
+        assert_eq!(size.used_bytes, 0);
+        assert_eq!(size.file_count, 0);
+    }
+
+    #[tokio::test]
+    async fn test_get_dir_size_async_single_file() {
+        use std::fs::File;
+        use std::io::Write;
+        use tempfile::TempDir;
+
+        let temp_dir = TempDir::new().unwrap();
+        let file_path = temp_dir.path().join("test.txt");
+        let mut file = File::create(&file_path).unwrap();
+        file.write_all(b"Hello, World!").unwrap();
+
+        let size = get_dir_size_async(temp_dir.path()).await.unwrap();
+        assert_eq!(size.used_bytes, 13);
+        assert_eq!(size.file_count, 1);
+    }
+
+    #[tokio::test]
+    async fn test_get_dir_size_async_multiple_files() {
+        use std::fs::File;
+        use std::io::Write;
+        use tempfile::TempDir;
+
+        let temp_dir = TempDir::new().unwrap();
+
+        for i in 0..10 {
+            let file_path = temp_dir.path().join(format!("file_{}.txt", i));
+            let mut file = File::create(&file_path).unwrap();
+            file.write_all(b"test").unwrap();
+        }
+
+        let size = get_dir_size_async(temp_dir.path()).await.unwrap();
+        assert_eq!(size.used_bytes, 40);
+        assert_eq!(size.file_count, 10);
+    }
+
+    #[tokio::test]
+    async fn test_get_dir_size_async_nested_directories() {
+        use std::fs::File;
+        use std::io::Write;
+        use tempfile::TempDir;
+
+        let temp_dir = TempDir::new().unwrap();
+        let subdir = temp_dir.path().join("subdir");
+        std::fs::create_dir(&subdir).unwrap();
+
+        let file1 = temp_dir.path().join("file1.txt");
+        let mut f1 = File::create(&file1).unwrap();
+        f1.write_all(b"content1").unwrap();
+
+        let file2 = subdir.join("file2.txt");
+        let mut f2 = File::create(&file2).unwrap();
+        f2.write_all(b"content2").unwrap();
+
+        let size = get_dir_size_async(temp_dir.path()).await.unwrap();
+        assert_eq!(size.used_bytes, 16);
+        assert_eq!(size.file_count, 2);
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_get_dir_size_async_nonexistent_directory() {
+        let result = get_dir_size_async(Path::new("/nonexistent/path")).await;
+        assert!(result.is_err());
+    }
+
+    #[tokio::test]
+    async fn test_calculate_data_dir_used_capacity_returns_partial_success() {
+        use std::fs::File;
+        use std::io::Write;
+        use tempfile::TempDir;
+
+        let temp_dir = TempDir::new().unwrap();
+        let file_path = temp_dir.path().join("test.txt");
+        let mut file = File::create(&file_path).unwrap();
+        file.write_all(b"Hello, World!").unwrap();
+
+        let disks = vec![
+            CapacityDiskRef {
+                endpoint: "disk-1".to_string(),
+                drive_path: temp_dir.path().to_string_lossy().into_owned(),
+            },
+            CapacityDiskRef {
+                endpoint: "disk-2".to_string(),
+                drive_path: "/nonexistent/path".to_string(),
+            },
+        ];
+
+        let result = calculate_data_dir_used_capacity(&disks).await.unwrap();
+        assert_eq!(result.used_bytes, 13);
+        assert_eq!(result.file_count, 1);
+        assert!(result.had_partial_errors);
+    }
+
+    #[tokio::test]
+    async fn test_select_capacity_refresh_disks_returns_full_when_disk_cache_incomplete() {
+        let manager = create_isolated_manager(HybridStrategyConfig::default());
+        manager
+            .mark_dirty_scope(&CapacityScope {
+                disks: vec![CapacityScopeDisk {
+                    endpoint: "disk-1".to_string(),
+                    drive_path: "/tmp/disk-1".to_string(),
+                }],
+            })
+            .await;
+
+        let disks = vec![
+            CapacityDiskRef {
+                endpoint: "disk-1".to_string(),
+                drive_path: "/tmp/disk-1".to_string(),
+            },
+            CapacityDiskRef {
+                endpoint: "disk-2".to_string(),
+                drive_path: "/tmp/disk-2".to_string(),
+            },
+        ];
+
+        let (selected, dirty_subset) = select_capacity_refresh_disks(manager.as_ref(), &disks).await;
+        assert!(!dirty_subset);
+        assert_eq!(selected.len(), 2);
+    }
+
+    #[tokio::test]
+    async fn test_select_capacity_refresh_disks_returns_dirty_subset_when_cache_complete() {
+        let manager = create_isolated_manager(HybridStrategyConfig::default());
+        manager
+            .update_capacity(
+                CapacityUpdate {
+                    total_used: 300,
+                    file_count: 3,
+                    is_estimated: false,
+                    per_disk: vec![
+                        DiskCapacityUpdate {
+                            disk: CapacityScopeDisk {
+                                endpoint: "disk-1".to_string(),
+                                drive_path: "/tmp/disk-1".to_string(),
+                            },
+                            used_bytes: 100,
+                            file_count: 1,
+                            is_estimated: false,
+                        },
+                        DiskCapacityUpdate {
+                            disk: CapacityScopeDisk {
+                                endpoint: "disk-2".to_string(),
+                                drive_path: "/tmp/disk-2".to_string(),
+                            },
+                            used_bytes: 200,
+                            file_count: 2,
+                            is_estimated: false,
+                        },
+                    ],
+                    expected_disk_count: Some(2),
+                    replaces_disk_cache: true,
+                    clear_dirty_disks: Vec::new(),
+                },
+                DataSource::RealTime,
+            )
+            .await;
+        manager
+            .mark_dirty_scope(&CapacityScope {
+                disks: vec![CapacityScopeDisk {
+                    endpoint: "disk-2".to_string(),
+                    drive_path: "/tmp/disk-2".to_string(),
+                }],
+            })
+            .await;
+
+        let disks = vec![
+            CapacityDiskRef {
+                endpoint: "disk-1".to_string(),
+                drive_path: "/tmp/disk-1".to_string(),
+            },
+            CapacityDiskRef {
+                endpoint: "disk-2".to_string(),
+                drive_path: "/tmp/disk-2".to_string(),
+            },
+        ];
+
+        let (selected, dirty_subset) = select_capacity_refresh_disks(manager.as_ref(), &disks).await;
+        assert!(dirty_subset);
+        assert_eq!(selected.len(), 1);
+        assert_eq!(selected[0].endpoint, "disk-2");
+        assert_eq!(selected[0].drive_path, "/tmp/disk-2");
+    }
+
+    #[cfg(unix)]
+    #[tokio::test]
+    #[serial]
+    async fn test_get_dir_size_async_ignores_symlink_targets_when_follow_disabled() {
+        use std::fs::File;
+        use std::io::Write;
+        use std::os::unix::fs::symlink;
+        use tempfile::TempDir;
+
+        let scan_dir = TempDir::new().unwrap();
+        let target_dir = TempDir::new().unwrap();
+        let target_path = target_dir.path().join("external.txt");
+        let mut file = File::create(&target_path).unwrap();
+        file.write_all(b"external-bytes").unwrap();
+        symlink(&target_path, scan_dir.path().join("external-link")).unwrap();
+
+        let size = temp_env::async_with_vars([(ENV_CAPACITY_FOLLOW_SYMLINKS, Some("false"))], async {
+            get_dir_size_async(scan_dir.path()).await
+        })
+        .await
+        .unwrap();
+
+        assert_eq!(size.used_bytes, 0);
+        assert_eq!(size.file_count, 0);
+    }
+
+    #[cfg(unix)]
+    #[tokio::test]
+    #[serial]
+    async fn test_get_dir_size_async_counts_symlink_targets_when_follow_enabled() {
+        use std::fs::File;
+        use std::io::Write;
+        use std::os::unix::fs::symlink;
+        use tempfile::TempDir;
+
+        let scan_dir = TempDir::new().unwrap();
+        let target_dir = TempDir::new().unwrap();
+        let target_path = target_dir.path().join("external.txt");
+        let mut file = File::create(&target_path).unwrap();
+        file.write_all(b"external-bytes").unwrap();
+        symlink(&target_path, scan_dir.path().join("external-link")).unwrap();
+
+        let size = temp_env::async_with_vars([(ENV_CAPACITY_FOLLOW_SYMLINKS, Some("true"))], async {
+            get_dir_size_async(scan_dir.path()).await
+        })
+        .await
+        .unwrap();
+
+        assert_eq!(size.used_bytes, "external-bytes".len() as u64);
+        assert_eq!(size.file_count, 1);
+    }
+}
diff --git a/crates/object-capacity/src/types.rs b/crates/object-capacity/src/types.rs
new file mode 100644
index 000000000..6f867ac2b
--- /dev/null
+++ b/crates/object-capacity/src/types.rs
@@ -0,0 +1,62 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::time::Duration;
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct CapacityDiskRef {
+    pub endpoint: String,
+    pub drive_path: String,
+}
+
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
+pub(crate) struct CapacityScanResult {
+    pub used_bytes: u64,
+    pub file_count: usize,
+    pub sampled_count: usize,
+    pub is_estimated: bool,
+    pub scan_duration: Duration,
+    pub had_partial_errors: bool,
+}
+
+impl CapacityScanResult {
+    pub(crate) fn with_partial_errors(mut self) -> Self {
+        self.had_partial_errors = true;
+        self
+    }
+}
+
+/// Public summary type for external tooling such as benches.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct CapacityScanSummary {
+    pub used_bytes: u64,
+    pub file_count: usize,
+    pub sampled_count: usize,
+    pub is_estimated: bool,
+    pub had_partial_errors: bool,
+    pub scan_duration: Duration,
+}
+
+impl From<CapacityScanResult> for CapacityScanSummary {
+    fn from(scan: CapacityScanResult) -> Self {
+        Self {
+            used_bytes: scan.used_bytes,
+            file_count: scan.file_count,
+            sampled_count: scan.sampled_count,
+            is_estimated: scan.is_estimated,
+            had_partial_errors: scan.had_partial_errors,
+            scan_duration: scan.scan_duration,
+        }
+    }
+}
diff --git a/rustfs/Cargo.toml b/rustfs/Cargo.toml
index 3b314d08e..2242d4598 100644
--- a/rustfs/Cargo.toml
+++ b/rustfs/Cargo.toml
@@ -91,6 +91,7 @@ rustfs-zip = { workspace = true }
 rustfs-io-core = { workspace = true }
 rustfs-io-metrics = { workspace = true }
 rustfs-object-io = { workspace = true }
+rustfs-object-capacity = { workspace = true }
 rustfs-concurrency = { workspace = true }
 rustfs-scanner = { workspace = true }
 tempfile = { workspace = true }
@@ -119,7 +120,6 @@ tower-http = { workspace = true, features = ["trace", "compression-full", "cors"
 # Serialization and Data Formats
 bytes = { workspace = true }
 flatbuffers.workspace = true
-walkdir = { workspace = true }
 rmp-serde.workspace = true
 rustfs-signer.workspace = true
 serde.workspace = true
@@ -197,7 +197,7 @@ tempfile = { workspace = true }
 aws-config = { workspace = true }
 anyhow = { workspace = true }
 tokio = { workspace = true, features = ["test-util"] }
-temp-env = { workspace = true }
+temp-env = { workspace = true, features = ["async_closure"] }
 
 [build-dependencies]
 http.workspace = true
diff --git a/rustfs/src/app/admin_usecase.rs b/rustfs/src/app/admin_usecase.rs
index 8b4d5117f..616b21d2c 100644
--- a/rustfs/src/app/admin_usecase.rs
+++ b/rustfs/src/app/admin_usecase.rs
@@ -15,10 +15,7 @@
 //! Admin application use-case contracts.
 
 use crate::app::context::{AppContext, get_global_app_context};
-use crate::capacity::capacity_manager::{
-    CapacityUpdate, DataSource, get_capacity_manager, get_enable_dynamic_timeout, get_follow_symlinks, get_max_files_threshold,
-    get_max_symlink_depth, get_max_timeout, get_min_timeout, get_sample_rate, get_stall_timeout, get_stat_timeout,
-};
+use crate::capacity::resolve_admin_used_capacity;
 use crate::error::ApiError;
 use rustfs_common::data_usage::DataUsageInfo;
 use rustfs_ecstore::admin_server_info::get_server_info;
@@ -27,18 +24,10 @@ use rustfs_ecstore::endpoints::EndpointServerPools;
 use rustfs_ecstore::new_object_layer_fn;
 use rustfs_ecstore::pools::{PoolStatus, get_total_usable_capacity, get_total_usable_capacity_free};
 use rustfs_ecstore::store_api::StorageAPI;
-use rustfs_io_metrics::{
-    record_capacity_dynamic_timeout, record_capacity_scan_sampling, record_capacity_stall_detected, record_capacity_symlink,
-    record_capacity_timeout_fallback,
-};
 use rustfs_madmin::{InfoMessage, StorageInfo};
 use s3s::S3ErrorCode;
-use std::collections::HashSet;
-use std::path::{Path, PathBuf};
 use std::sync::Arc;
-use std::time::{Duration, Instant};
 use tracing::{debug, error, info, warn};
-use walkdir::WalkDir;
 
 pub type AdminUsecaseResult<T> = Result<T, ApiError>;
 
@@ -47,31 +36,6 @@ pub struct QueryServerInfoRequest {
     pub include_pools: bool,
 }
 
-#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
-pub(crate) struct CapacityScanResult {
-    pub used_bytes: u64,
-    pub file_count: usize,
-    pub sampled_count: usize,
-    pub is_estimated: bool,
-    pub scan_duration: Duration,
-    pub had_partial_errors: bool,
-}
-
-impl CapacityScanResult {
-    fn with_partial_errors(mut self) -> Self {
-        self.had_partial_errors = true;
-        self
-    }
-
-    pub(crate) fn to_capacity_update(self) -> CapacityUpdate {
-        if self.is_estimated {
-            CapacityUpdate::estimated(self.used_bytes, self.file_count)
-        } else {
-            CapacityUpdate::exact(self.used_bytes, self.file_count)
-        }
-    }
-}
-
 pub struct QueryServerInfoResponse {
     pub info: InfoMessage,
 }
@@ -94,475 +58,6 @@ pub struct QueryPoolStatusRequest {
     pub by_id: bool,
 }
 
-/// Calculate actual used capacity of all data directories
-pub(crate) async fn calculate_data_dir_used_capacity(
-    disks: &[rustfs_madmin::Disk],
-) -> Result<CapacityScanResult, Box<dyn std::error::Error + Send + Sync>> {
-    let start = Instant::now();
-    let mut total_used = 0u64;
-    let mut total_files = 0usize;
-    let mut total_sampled = 0usize;
-    let mut has_failure = false;
-    let mut has_success = false;
-    let mut is_estimated = false;
-
-    for disk in disks {
-        let path = Path::new(&disk.drive_path);
-
-        if !path.exists() {
-            warn!("Data directory does not exist: {}", disk.drive_path);
-            has_failure = true;
-            continue;
-        }
-
-        match get_dir_size_async(path).await {
-            Ok(scan) => {
-                debug!(
-                    "Data directory {} size: {} bytes, files={}, sampled={}, estimated={}",
-                    disk.drive_path, scan.used_bytes, scan.file_count, scan.sampled_count, scan.is_estimated
-                );
-                total_used += scan.used_bytes;
-                total_files += scan.file_count;
-                total_sampled += scan.sampled_count;
-                is_estimated |= scan.is_estimated;
-                has_failure |= scan.had_partial_errors;
-                has_success = true;
-            }
-            Err(e) => {
-                warn!("Failed to get size for directory {}: {:?}", disk.drive_path, e);
-                has_failure = true;
-            }
-        }
-    }
-
-    if !has_success {
-        return Err("All directories failed to calculate size".into());
-    }
-
-    if has_failure {
-        warn!("Some directories failed to calculate size, result may be incomplete");
-    }
-
-    let mut result = CapacityScanResult {
-        used_bytes: total_used,
-        file_count: total_files,
-        sampled_count: total_sampled,
-        is_estimated,
-        scan_duration: start.elapsed(),
-        had_partial_errors: false,
-    };
-
-    if has_failure {
-        result = result.with_partial_errors();
-    }
-
-    Ok(result)
-}
-
-// ============================================================================
-// Symlink Tracker for Circular Reference Detection
-// ============================================================================
-
-/// Tracker for symlink resolution with circular reference detection
-struct SymlinkTracker {
-    /// Set of visited symlink paths to detect circular references
-    visited: HashSet<PathBuf>,
-    /// Count of symlinks encountered
-    symlink_count: usize,
-    /// Total size of symlink targets
-    symlink_size: u64,
-    /// Maximum symlink depth to follow
-    max_depth: u8,
-}
-
-impl SymlinkTracker {
-    /// Create a new symlink tracker
-    fn new(max_depth: u8) -> Self {
-        Self {
-            visited: HashSet::new(),
-            symlink_count: 0,
-            symlink_size: 0,
-            max_depth,
-        }
-    }
-
-    /// Check if we should follow a symlink at the given depth
-    fn should_follow(&self, path: &Path, depth: u8) -> bool {
-        if depth >= self.max_depth {
-            debug!("Symlink depth limit reached: {} >= {}, not following {:?}", depth, self.max_depth, path);
-            return false;
-        }
-
-        if self.visited.contains(path) {
-            warn!("Circular symlink reference detected: {:?}, skipping", path);
-            return false;
-        }
-
-        true
-    }
-
-    /// Record a visited symlink path and update metrics
-    fn record_symlink(&mut self, path: PathBuf, size: u64) {
-        self.visited.insert(path);
-        self.symlink_count += 1;
-        self.symlink_size += size;
-        record_capacity_symlink(size);
-    }
-
-    /// Get symlink statistics
-    fn get_stats(&self) -> (usize, u64) {
-        (self.symlink_count, self.symlink_size)
-    }
-}
-
-// ============================================================================
-// Progress Monitor for Timeout and Stall Detection
-// ============================================================================
-
-/// Monitor for directory traversal progress with timeout and stall detection
-struct ProgressMonitor {
-    /// Start time of the operation
-    start_time: Instant,
-    /// Last check time for stall detection
-    last_check: Instant,
-    /// Number of files processed at last checkpoint
-    last_checkpoint_files: usize,
-    /// Base timeout for this operation
-    timeout: Duration,
-    /// Minimum allowed timeout
-    min_timeout: Duration,
-    /// Maximum allowed timeout
-    max_timeout: Duration,
-    /// Stall detection timeout
-    stall_timeout: Duration,
-    /// Enable dynamic timeout calculation
-    enable_dynamic_timeout: bool,
-    /// Track if dynamic timeout was used
-    used_dynamic_timeout: bool,
-}
-
-impl ProgressMonitor {
-    /// Create a new progress monitor
-    fn new(
-        base_timeout: Duration,
-        min_timeout: Duration,
-        max_timeout: Duration,
-        stall_timeout: Duration,
-        enable_dynamic: bool,
-    ) -> Self {
-        Self {
-            start_time: Instant::now(),
-            last_check: Instant::now(),
-            last_checkpoint_files: 0,
-            timeout: base_timeout,
-            min_timeout,
-            max_timeout,
-            stall_timeout,
-            enable_dynamic_timeout: enable_dynamic,
-            used_dynamic_timeout: false,
-        }
-    }
-
-    /// Calculate dynamic timeout based on directory characteristics
-    fn calculate_dynamic_timeout(&mut self, file_count: usize, avg_file_size: u64) -> Duration {
-        if !self.enable_dynamic_timeout {
-            return self.timeout;
-        }
-
-        // Mark that we're using dynamic timeout
-        self.used_dynamic_timeout = true;
-
-        // Calculate multipliers based on directory characteristics
-        let file_factor = (file_count as f64).sqrt() * 0.01; // File count influence
-        let size_factor = if avg_file_size > 0 {
-            (avg_file_size as f64).log(10.0) * 0.05 // File size influence
-        } else {
-            0.0
-        };
-
-        let multiplier = 1.0 + file_factor + size_factor;
-        let adjusted_timeout = self.timeout.mul_f64(multiplier.min(5.0)); // Max 5x multiplier
-
-        // Clamp to min/max bounds
-        let clamped_timeout = adjusted_timeout.max(self.min_timeout).min(self.max_timeout);
-
-        debug!(
-            "Dynamic timeout calculation: files={}, avg_size={}, multiplier={:.2}, base_timeout={:?}, adjusted_timeout={:?}, clamped_timeout={:?}",
-            file_count, avg_file_size, multiplier, self.timeout, adjusted_timeout, clamped_timeout
-        );
-
-        clamped_timeout
-    }
-
-    /// Update and check for timeout or stall
-    fn update_and_check_timeout(&mut self, files_processed: usize, avg_file_size: u64) -> Result<(), std::io::Error> {
-        let elapsed = self.start_time.elapsed();
-
-        // Calculate dynamic timeout based on current state
-        let dynamic_timeout = if self.enable_dynamic_timeout {
-            self.calculate_dynamic_timeout(files_processed, avg_file_size)
-        } else {
-            self.timeout
-        };
-
-        // Check for hard timeout
-        if elapsed >= dynamic_timeout {
-            warn!(
-                "Directory size calculation timeout after {} files, elapsed: {:?}, timeout: {:?}",
-                files_processed, elapsed, dynamic_timeout
-            );
-
-            if self.enable_dynamic_timeout {
-                record_capacity_dynamic_timeout(dynamic_timeout);
-            }
-
-            return Err(std::io::Error::new(
-                std::io::ErrorKind::TimedOut,
-                format!("Timeout after {} files", files_processed),
-            ));
-        }
-
-        // Check for stall (no progress)
-        let now = Instant::now();
-        if now.duration_since(self.last_check) >= self.stall_timeout {
-            let files_per_checkpoint = files_processed.saturating_sub(self.last_checkpoint_files);
-
-            if files_per_checkpoint == 0 && files_processed > 0 {
-                // No progress for stall_timeout duration
-                warn!(
-                    "No progress detected for {:?}, possible stall at {} files",
-                    self.stall_timeout, files_processed
-                );
-
-                record_capacity_stall_detected();
-
-                return Err(std::io::Error::new(
-                    std::io::ErrorKind::TimedOut,
-                    format!("Stall detected at {} files", files_processed),
-                ));
-            }
-
-            self.last_check = now;
-            self.last_checkpoint_files = files_processed;
-        }
-
-        Ok(())
-    }
-
-    /// Record timeout fallback to sampling
-    fn record_timeout_fallback(&self) {
-        record_capacity_timeout_fallback();
-    }
-}
-
-/// Asynchronously get directory size with enhanced symlink handling and dynamic timeout
-async fn get_dir_size_async(path: &Path) -> Result<CapacityScanResult, std::io::Error> {
-    let path = path.to_path_buf();
-
-    let max_files_threshold = get_max_files_threshold();
-    let base_timeout = get_stat_timeout();
-    let min_timeout = get_min_timeout();
-    let max_timeout = get_max_timeout();
-    let stall_timeout = get_stall_timeout();
-    let sample_rate = get_sample_rate();
-    let enable_dynamic_timeout = get_enable_dynamic_timeout();
-    let follow_symlinks = get_follow_symlinks();
-    let max_symlink_depth = get_max_symlink_depth();
-
-    let effective_sample_rate = if sample_rate == 0 {
-        warn!("Invalid sampling configuration: sample_rate=0. Clamping to 1 to avoid panic.");
-        1
-    } else {
-        sample_rate
-    };
-
-    if !path.exists() {
-        return Err(std::io::Error::new(
-            std::io::ErrorKind::NotFound,
-            format!("Directory not found: {:?}", path),
-        ));
-    }
-
-    tokio::task::spawn_blocking(move || {
-        let start_time = Instant::now();
-        let mut exact_prefix_bytes = 0u64;
-        let mut overflow_sampled_bytes = 0u64;
-        let mut file_count = 0usize;
-        let mut sampled_count = 0usize;
-        let mut had_partial_errors = false;
-
-        let mut symlink_tracker = if follow_symlinks {
-            Some(SymlinkTracker::new(max_symlink_depth))
-        } else {
-            None
-        };
-
-        let mut progress_monitor =
-            ProgressMonitor::new(base_timeout, min_timeout, max_timeout, stall_timeout, enable_dynamic_timeout);
-
-        let mut walker_builder = WalkDir::new(&path);
-        if !follow_symlinks {
-            walker_builder = walker_builder.follow_links(false);
-        }
-        let walker = walker_builder.into_iter();
-
-        for entry_result in walker {
-            let entry = match entry_result {
-                Ok(entry) => entry,
-                Err(err) => {
-                    warn!("Failed to traverse directory entry under {:?}: {}", path, err);
-                    had_partial_errors = true;
-                    continue;
-                }
-            };
-
-            let metadata = match entry.metadata() {
-                Ok(meta) => meta,
-                Err(err) => {
-                    warn!("Failed to get metadata for {:?}: {}", entry.path(), err);
-                    had_partial_errors = true;
-                    continue;
-                }
-            };
-
-            if metadata.is_symlink() {
-                if let Some(ref mut tracker) = symlink_tracker
-                    && let Ok(target) = std::fs::read_link(entry.path())
-                    && tracker.should_follow(&target, 0)
-                {
-                    tracker.record_symlink(target, metadata.len());
-                }
-                continue;
-            }
-
-            if !metadata.is_file() {
-                continue;
-            }
-
-            file_count += 1;
-            let exact_count = file_count.min(max_files_threshold);
-            let avg_size = if exact_count > 0 {
-                exact_prefix_bytes / exact_count as u64
-            } else {
-                0
-            };
-
-            if let Err(e) = progress_monitor.update_and_check_timeout(file_count, avg_size) {
-                if sampled_count > 0 {
-                    let overflow_count = file_count.saturating_sub(max_files_threshold);
-                    let estimated_overflow = overflow_sampled_bytes.saturating_mul(overflow_count as u64) / sampled_count as u64;
-                    let estimated_total = exact_prefix_bytes.saturating_add(estimated_overflow);
-                    info!(
-                        "Timeout/stall at {} files, using sampled estimate: exact_prefix={} overflow_estimate={} sampled={}",
-                        file_count, exact_prefix_bytes, estimated_overflow, sampled_count
-                    );
-                    progress_monitor.record_timeout_fallback();
-                    record_capacity_scan_sampling(sampled_count, true);
-                    return Ok(CapacityScanResult {
-                        used_bytes: estimated_total,
-                        file_count,
-                        sampled_count,
-                        is_estimated: true,
-                        scan_duration: start_time.elapsed(),
-                        had_partial_errors,
-                    });
-                }
-                return Err(e);
-            }
-
-            if file_count <= max_files_threshold {
-                exact_prefix_bytes += metadata.len();
-            } else {
-                let overflow_index = file_count - max_files_threshold;
-                if overflow_index.is_multiple_of(effective_sample_rate) {
-                    overflow_sampled_bytes += metadata.len();
-                    sampled_count += 1;
-                }
-
-                if file_count.is_multiple_of(100_000) {
-                    debug!(
-                        "Processed {} files, exact_prefix_bytes={}, sampled_overflow={} files/{} bytes",
-                        file_count, exact_prefix_bytes, sampled_count, overflow_sampled_bytes
-                    );
-                }
-            }
-        }
-
-        if let Some(tracker) = symlink_tracker {
-            let (count, size) = tracker.get_stats();
-            if count > 0 {
-                info!("Symlink tracking: {} symlinks processed, total target size: {} bytes", count, size);
-            }
-        }
-
-        if file_count > max_files_threshold && sampled_count > 0 {
-            let overflow_count = file_count - max_files_threshold;
-            let estimated_overflow = overflow_sampled_bytes.saturating_mul(overflow_count as u64) / sampled_count as u64;
-            let estimated_size = exact_prefix_bytes.saturating_add(estimated_overflow);
-            info!(
-                "Large directory detected: {} files, estimated size: {} bytes (exact prefix: {}, sampled overflow {}/{})",
-                file_count, estimated_size, exact_prefix_bytes, sampled_count, overflow_count
-            );
-            record_capacity_scan_sampling(sampled_count, true);
-            Ok(CapacityScanResult {
-                used_bytes: estimated_size,
-                file_count,
-                sampled_count,
-                is_estimated: true,
-                scan_duration: start_time.elapsed(),
-                had_partial_errors,
-            })
-        } else if file_count > max_files_threshold {
-            // sampled_count == 0: too few overflow files to reach the sample rate threshold.
-            // Fall back to estimating the overflow using the average file size from the exact
-            // prefix so that overflow files are not silently dropped from the total.
-            let overflow_count = file_count - max_files_threshold;
-            // Use the actual number of files counted in the exact prefix, not the threshold
-            // value, to avoid a divide-by-zero or incorrect average when fewer files were
-            // processed than max_files_threshold.
-            let exact_prefix_count = file_count.min(max_files_threshold) as u64;
-            let avg_prefix_size = if exact_prefix_count > 0 {
-                exact_prefix_bytes / exact_prefix_count
-            } else {
-                0
-            };
-            let estimated_overflow = avg_prefix_size.saturating_mul(overflow_count as u64);
-            let estimated_size = exact_prefix_bytes.saturating_add(estimated_overflow);
-            info!(
-                "Large directory detected: {} files, estimated size: {} bytes (no overflow samples, used prefix average {} bytes/file)",
-                file_count, estimated_size, avg_prefix_size
-            );
-            record_capacity_scan_sampling(0, true);
-            Ok(CapacityScanResult {
-                used_bytes: estimated_size,
-                file_count,
-                sampled_count: 0,
-                is_estimated: true,
-                scan_duration: start_time.elapsed(),
-                had_partial_errors,
-            })
-        } else {
-            record_capacity_scan_sampling(0, false);
-            debug!(
-                "Directory size calculation completed: {} files, {} bytes, took {:?}",
-                file_count,
-                exact_prefix_bytes,
-                start_time.elapsed()
-            );
-            Ok(CapacityScanResult {
-                used_bytes: exact_prefix_bytes,
-                file_count,
-                sampled_count,
-                is_estimated: false,
-                scan_duration: start_time.elapsed(),
-                had_partial_errors,
-            })
-        }
-    })
-    .await
-    .map_err(std::io::Error::other)?
-}
-
 #[derive(Clone, Default)]
 pub struct DefaultAdminUsecase {
     context: Option<Arc<AppContext>>,
@@ -688,115 +183,8 @@ impl DefaultAdminUsecase {
             info.total_free_capacity = free_u64;
         }
 
-        // Use hybrid strategy for capacity calculation
-        let capacity_manager = get_capacity_manager();
-
-        // Check if we have a valid cache
-        if let Some(cached) = capacity_manager.get_capacity().await {
-            let cache_age = cached.last_update.elapsed();
-            let fast_update_threshold = capacity_manager.get_config().fast_update_threshold;
-
-            // If cache is fresh (< fast_update_threshold), use it directly
-            if cache_age < fast_update_threshold {
-                info.total_used_capacity = cached.total_used;
-                debug!(
-                    "Using cached capacity: {} bytes (age: {:?}, source: {:?}, files={}, estimated={})",
-                    cached.total_used, cache_age, cached.source, cached.file_count, cached.is_estimated
-                );
-            } else {
-                // Cache is stale, check if we need fast update
-                let needs_update = capacity_manager.needs_fast_update().await;
-                let should_block = capacity_manager.should_block_on_refresh(cache_age);
-
-                if needs_update && should_block {
-                    let start = Instant::now();
-                    match capacity_manager
-                        .refresh_or_join(DataSource::WriteTriggered, || async {
-                            calculate_data_dir_used_capacity(&storage_info.disks)
-                                .await
-                                .map(|scan| scan.to_capacity_update())
-                                .map_err(|e| e.to_string())
-                        })
-                        .await
-                    {
-                        Ok(update) => {
-                            info.total_used_capacity = update.total_used;
-
-                            let elapsed = start.elapsed();
-                            debug!(
-                                "Foreground capacity refresh completed in {:?} (files={}, estimated={})",
-                                elapsed, update.file_count, update.is_estimated
-                            );
-                        }
-                        Err(e) => {
-                            warn!("Foreground capacity refresh failed: {}, using cached value", e);
-                            info.total_used_capacity = cached.total_used;
-                        }
-                    }
-                } else {
-                    info.total_used_capacity = cached.total_used;
-                    debug!(
-                        "Using stale cached capacity: {} bytes (age: {:?}, source: {:?}, files={}, estimated={}, needs_update={}, blocking={})",
-                        cached.total_used,
-                        cache_age,
-                        cached.source,
-                        cached.file_count,
-                        cached.is_estimated,
-                        needs_update,
-                        should_block
-                    );
-
-                    let disks = storage_info.disks.clone();
-                    let manager = capacity_manager.clone();
-                    if manager
-                        .clone()
-                        .spawn_refresh_if_needed(DataSource::Scheduled, move || async move {
-                            calculate_data_dir_used_capacity(&disks)
-                                .await
-                                .map(|scan| scan.to_capacity_update())
-                                .map_err(|e| e.to_string())
-                        })
-                        .await
-                    {
-                        debug!("Background capacity update started");
-                    } else {
-                        debug!("Background update already in progress, skipping spawn");
-                    }
-                }
-            }
-        } else {
-            // No cache, perform initial calculation
-            let start = Instant::now();
-            match capacity_manager
-                .refresh_or_join(DataSource::RealTime, || async {
-                    calculate_data_dir_used_capacity(&storage_info.disks)
-                        .await
-                        .map(|scan| scan.to_capacity_update())
-                        .map_err(|e| e.to_string())
-                })
-                .await
-            {
-                Ok(update) => {
-                    info.total_used_capacity = update.total_used;
-
-                    let elapsed = start.elapsed();
-                    info!(
-                        "Initial capacity calculation completed: {} bytes in {:?} (files={}, estimated={})",
-                        update.total_used, elapsed, update.file_count, update.is_estimated
-                    );
-                }
-                Err(e) => {
-                    warn!(
-                        "Failed to calculate data directory used capacity: {}, falling back to disk used capacity",
-                        e
-                    );
-                    info.total_used_capacity = info.total_capacity.saturating_sub(info.total_free_capacity);
-                    capacity_manager
-                        .update_capacity(CapacityUpdate::fallback(info.total_used_capacity), DataSource::Fallback)
-                        .await;
-                }
-            }
-        }
+        info.total_used_capacity =
+            resolve_admin_used_capacity(&storage_info.disks, info.total_capacity.saturating_sub(info.total_free_capacity)).await;
         debug!(
             "Capacity statistics: total={:.2} TiB, free={:.2} TiB, used={:.2} TiB",
             info.total_capacity as f64 / (1024.0_f64.powi(4)),
@@ -885,7 +273,6 @@ impl DefaultAdminUsecase {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use serial_test::serial;
 
     #[tokio::test]
     async fn execute_query_storage_info_returns_internal_error_when_store_uninitialized() {
@@ -911,83 +298,4 @@ mod tests {
         let _ = readiness.storage_ready;
         let _ = readiness.iam_ready;
     }
-
-    // Tests for directory size calculation functions
-    #[tokio::test]
-    async fn test_get_dir_size_async_empty_directory() {
-        use tempfile::TempDir;
-
-        let temp_dir = TempDir::new().unwrap();
-        let size = get_dir_size_async(temp_dir.path()).await.unwrap();
-        assert_eq!(size.used_bytes, 0);
-        assert_eq!(size.file_count, 0);
-    }
-
-    #[tokio::test]
-    async fn test_get_dir_size_async_single_file() {
-        use std::fs::File;
-        use std::io::Write;
-        use tempfile::TempDir;
-
-        let temp_dir = TempDir::new().unwrap();
-        let file_path = temp_dir.path().join("test.txt");
-        let mut file = File::create(&file_path).unwrap();
-        file.write_all(b"Hello, World!").unwrap();
-
-        let size = get_dir_size_async(temp_dir.path()).await.unwrap();
-        assert_eq!(size.used_bytes, 13);
-        assert_eq!(size.file_count, 1);
-    }
-
-    #[tokio::test]
-    async fn test_get_dir_size_async_multiple_files() {
-        use std::fs::File;
-        use std::io::Write;
-        use tempfile::TempDir;
-
-        let temp_dir = TempDir::new().unwrap();
-
-        // Create multiple files
-        for i in 0..10 {
-            let file_path = temp_dir.path().join(format!("file_{}.txt", i));
-            let mut file = File::create(&file_path).unwrap();
-            file.write_all(b"test").unwrap();
-        }
-
-        let size = get_dir_size_async(temp_dir.path()).await.unwrap();
-        assert_eq!(size.used_bytes, 40); // 10 files * 4 bytes
-        assert_eq!(size.file_count, 10);
-    }
-
-    #[tokio::test]
-    async fn test_get_dir_size_async_nested_directories() {
-        use std::fs::File;
-        use std::io::Write;
-        use tempfile::TempDir;
-
-        let temp_dir = TempDir::new().unwrap();
-
-        // Create nested directories and files
-        let subdir = temp_dir.path().join("subdir");
-        std::fs::create_dir(&subdir).unwrap();
-
-        let file1 = temp_dir.path().join("file1.txt");
-        let mut f1 = File::create(&file1).unwrap();
-        f1.write_all(b"content1").unwrap();
-
-        let file2 = subdir.join("file2.txt");
-        let mut f2 = File::create(&file2).unwrap();
-        f2.write_all(b"content2").unwrap();
-
-        let size = get_dir_size_async(temp_dir.path()).await.unwrap();
-        assert_eq!(size.used_bytes, 16); // "content1" (8) + "content2" (8)
-        assert_eq!(size.file_count, 2);
-    }
-
-    #[tokio::test]
-    #[serial]
-    async fn test_get_dir_size_async_nonexistent_directory() {
-        let result = get_dir_size_async(Path::new("/nonexistent/path")).await;
-        assert!(result.is_err());
-    }
 }
diff --git a/rustfs/src/app/bucket_usecase.rs b/rustfs/src/app/bucket_usecase.rs
index 073753add..d08eae838 100644
--- a/rustfs/src/app/bucket_usecase.rs
+++ b/rustfs/src/app/bucket_usecase.rs
@@ -1494,10 +1494,7 @@ impl DefaultBucketUsecase {
             && let Some(store) = new_object_layer_fn()
         {
             let bucket_name = bucket.clone();
-            let request_context = req
-                .extensions
-                .get::<crate::storage::request_context::RequestContext>()
-                .cloned();
+            let request_context = req.extensions.get::<request_context::RequestContext>().cloned();
             spawn_background_with_context(request_context, async move {
                 if let Err(err) = enqueue_transition_for_existing_objects(store, &bucket_name).await {
                     warn!(bucket = %bucket_name, error = ?err, "failed to enqueue transition for existing objects");
@@ -1883,7 +1880,7 @@ impl DefaultBucketUsecase {
 
         let store = get_validated_store(&bucket).await?;
 
-        let incl_deleted = rustfs_utils::http::get_header(&req.headers, rustfs_utils::http::SUFFIX_INCLUDE_DELETED)
+        let incl_deleted = get_header(&req.headers, rustfs_utils::http::SUFFIX_INCLUDE_DELETED)
             .map(|v| v.as_ref() == "true")
             .unwrap_or_default();
 
@@ -1963,7 +1960,7 @@ impl DefaultBucketUsecase {
             .transpose()?;
 
         let store = get_validated_store(&bucket).await?;
-        let incl_deleted = rustfs_utils::http::get_header(&req.headers, rustfs_utils::http::SUFFIX_INCLUDE_DELETED)
+        let incl_deleted = get_header(&req.headers, rustfs_utils::http::SUFFIX_INCLUDE_DELETED)
             .map(|value| value.as_ref() == "true")
             .unwrap_or_default();
 
diff --git a/rustfs/src/app/capacity_dirty_scope_test.rs b/rustfs/src/app/capacity_dirty_scope_test.rs
new file mode 100644
index 000000000..ad751340e
--- /dev/null
+++ b/rustfs/src/app/capacity_dirty_scope_test.rs
@@ -0,0 +1,224 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use rustfs_common::heal_channel::{HealOpts, HealScanMode};
+use rustfs_ecstore::{
+    bucket::metadata_sys,
+    disk::endpoint::Endpoint,
+    endpoints::{EndpointServerPools, Endpoints, PoolEndpoints},
+    store::ECStore,
+    store_api::{
+        BucketOperations, BucketOptions, ChunkNativePutData, HealOperations, MakeBucketOptions, ObjectIO, ObjectOptions,
+    },
+};
+use rustfs_object_capacity::capacity_manager::{HybridStrategyConfig, create_isolated_manager};
+use serial_test::serial;
+use std::{
+    collections::HashSet,
+    fs as stdfs,
+    path::Path,
+    path::PathBuf,
+    sync::{Arc, Once, OnceLock},
+};
+use tempfile::TempDir;
+use tokio::fs;
+use tokio_util::sync::CancellationToken;
+use uuid::Uuid;
+
+static CAPACITY_DIRTY_SCOPE_ENV: OnceLock<(Vec<PathBuf>, Arc<ECStore>, TempDir)> = OnceLock::new();
+static CAPACITY_DIRTY_SCOPE_INIT: Once = Once::new();
+
+fn init_capacity_dirty_scope_tracing() {
+    CAPACITY_DIRTY_SCOPE_INIT.call_once(|| {});
+}
+
+async fn setup_capacity_dirty_scope_env() -> (Vec<PathBuf>, Arc<ECStore>) {
+    init_capacity_dirty_scope_tracing();
+
+    if let Some((paths, store, _)) = CAPACITY_DIRTY_SCOPE_ENV.get() {
+        return (paths.clone(), store.clone());
+    }
+
+    let temp_dir = TempDir::new().expect("create temp dir for capacity dirty scope test");
+    let temp_path = temp_dir.path().to_path_buf();
+
+    let disk_paths = vec![
+        temp_path.join("disk1"),
+        temp_path.join("disk2"),
+        temp_path.join("disk3"),
+        temp_path.join("disk4"),
+    ];
+    for disk_path in &disk_paths {
+        fs::create_dir_all(disk_path).await.unwrap();
+    }
+
+    let mut endpoints = Vec::new();
+    for (i, disk_path) in disk_paths.iter().enumerate() {
+        let mut endpoint = Endpoint::try_from(disk_path.to_str().unwrap()).unwrap();
+        endpoint.set_pool_index(0);
+        endpoint.set_set_index(0);
+        endpoint.set_disk_index(i);
+        endpoints.push(endpoint);
+    }
+
+    let pool_endpoints = PoolEndpoints {
+        legacy: false,
+        set_count: 1,
+        drives_per_set: 4,
+        endpoints: Endpoints::from(endpoints),
+        cmd_line: "capacity-dirty-scope-test".to_string(),
+        platform: format!("OS: {} | Arch: {}", std::env::consts::OS, std::env::consts::ARCH),
+    };
+
+    let endpoint_pools = EndpointServerPools(vec![pool_endpoints]);
+    rustfs_ecstore::store::init_local_disks(endpoint_pools.clone()).await.unwrap();
+
+    let server_addr: std::net::SocketAddr = "127.0.0.1:0".parse().unwrap();
+    let ecstore = ECStore::new(server_addr, endpoint_pools, CancellationToken::new())
+        .await
+        .unwrap();
+
+    let buckets_list = ecstore
+        .list_bucket(&BucketOptions {
+            no_metadata: true,
+            ..Default::default()
+        })
+        .await
+        .unwrap();
+    let buckets = buckets_list.into_iter().map(|v| v.name).collect();
+    metadata_sys::init_bucket_metadata_sys(ecstore.clone(), buckets).await;
+
+    let _ = CAPACITY_DIRTY_SCOPE_ENV.set((disk_paths.clone(), ecstore.clone(), temp_dir));
+    (disk_paths, ecstore)
+}
+
+fn find_part_file(root: &Path, part_name: &str) -> Option<PathBuf> {
+    let entries = stdfs::read_dir(root).ok()?;
+    for entry in entries.flatten() {
+        let path = entry.path();
+        if path.is_dir() {
+            if let Some(found) = find_part_file(&path, part_name) {
+                return Some(found);
+            }
+            continue;
+        }
+
+        if path.file_name().and_then(|name| name.to_str()) == Some(part_name) {
+            return Some(path);
+        }
+    }
+
+    None
+}
+
+#[tokio::test]
+#[serial]
+async fn data_movement_put_object_marks_dirty_disks_for_capacity_manager() {
+    let (disk_paths, ecstore) = setup_capacity_dirty_scope_env().await;
+    let bucket_name = format!("dirty-scope-{}", Uuid::new_v4());
+
+    ecstore
+        .make_bucket(&bucket_name, &MakeBucketOptions::default())
+        .await
+        .expect("create test bucket");
+
+    let manager = create_isolated_manager(HybridStrategyConfig::default());
+    let _ = manager.get_dirty_disks().await;
+
+    let payload = b"data-movement-dirty-scope".to_vec();
+    let mut reader = ChunkNativePutData::from_vec(payload);
+    let opts = ObjectOptions {
+        data_movement: true,
+        src_pool_idx: 0,
+        ..Default::default()
+    };
+
+    ecstore
+        .put_object(&bucket_name, "object.bin", &mut reader, &opts)
+        .await
+        .expect("data movement put_object should succeed");
+
+    let dirty_disks = manager.get_dirty_disks().await;
+    assert_eq!(dirty_disks.len(), disk_paths.len());
+
+    let actual_paths: HashSet<_> = dirty_disks
+        .into_iter()
+        .map(|disk| stdfs::canonicalize(&disk.drive_path).unwrap().to_string_lossy().into_owned())
+        .collect();
+    let expected_paths: HashSet<_> = disk_paths
+        .iter()
+        .map(|path| stdfs::canonicalize(path).unwrap().to_string_lossy().into_owned())
+        .collect();
+    assert_eq!(actual_paths, expected_paths);
+}
+
+#[tokio::test]
+#[serial]
+async fn heal_object_marks_missing_shard_disk_dirty_for_capacity_manager() {
+    let (disk_paths, ecstore) = setup_capacity_dirty_scope_env().await;
+    let bucket_name = format!("dirty-heal-{}", Uuid::new_v4());
+
+    ecstore
+        .make_bucket(&bucket_name, &MakeBucketOptions::default())
+        .await
+        .expect("create test bucket");
+
+    let manager = create_isolated_manager(HybridStrategyConfig::default());
+    let _ = manager.get_dirty_disks().await;
+
+    let payload_len = 3 * 1024 * 1024 + 137;
+    let payload: Vec<u8> = (0..payload_len).map(|idx| (idx % 251) as u8).collect();
+    let mut reader = ChunkNativePutData::from_vec(payload);
+    let object_name = "test/heal.bin";
+    let put_info = ecstore
+        .put_object(&bucket_name, object_name, &mut reader, &ObjectOptions::default())
+        .await
+        .expect("put object for heal test");
+    assert!(put_info.data_blocks > 1, "expected multi-shard object for heal test");
+
+    let _ = manager.get_dirty_disks().await;
+
+    let object_root = disk_paths[0].join(&bucket_name).join("test").join("heal.bin");
+    let missing_part = find_part_file(&object_root, "part.1").expect("part file on first disk");
+    fs::remove_file(&missing_part).await.expect("remove shard to force heal");
+
+    let heal_opts = HealOpts {
+        recursive: false,
+        dry_run: false,
+        remove: false,
+        recreate: true,
+        scan_mode: HealScanMode::Deep,
+        update_parity: true,
+        no_lock: false,
+        pool: None,
+        set: None,
+    };
+
+    let (_result, error) = ecstore
+        .heal_object(&bucket_name, object_name, "", &heal_opts)
+        .await
+        .expect("heal_object call should succeed");
+
+    let dirty_disks = manager.get_dirty_disks().await;
+    let actual_paths: HashSet<_> = dirty_disks
+        .into_iter()
+        .map(|disk| stdfs::canonicalize(&disk.drive_path).unwrap().to_string_lossy().into_owned())
+        .collect();
+    let expected_missing_disk = stdfs::canonicalize(&disk_paths[0]).unwrap().to_string_lossy().into_owned();
+
+    assert!(
+        error.is_none() || actual_paths.contains(&expected_missing_disk),
+        "heal returned {error:?} and did not mark the repaired shard disk dirty: {actual_paths:?}"
+    );
+}
diff --git a/rustfs/src/app/lifecycle_transition_api_test.rs b/rustfs/src/app/lifecycle_transition_api_test.rs
index 8ed844525..03193697c 100644
--- a/rustfs/src/app/lifecycle_transition_api_test.rs
+++ b/rustfs/src/app/lifecycle_transition_api_test.rs
@@ -35,12 +35,14 @@ use rustfs_ecstore::{
         warm_backend::{WarmBackend, WarmBackendGetOpts},
     },
 };
+use rustfs_object_capacity::capacity_manager::{HybridStrategyConfig, create_isolated_manager};
 use rustfs_utils::http::{SUFFIX_FORCE_DELETE, insert_header};
 use s3s::{S3Request, dto::*};
 use serial_test::serial;
 use std::{
     collections::HashMap,
     convert::Infallible,
+    fs as stdfs,
     io::Cursor,
     path::PathBuf,
     sync::{Arc, Once, OnceLock},
@@ -539,3 +541,49 @@ async fn delete_transitioned_object_removes_remote_tier_copy_via_usecase() {
         "transitioned object should be removed from remote tier after delete usecase"
     );
 }
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+#[serial]
+#[ignore = "requires isolated global object layer state"]
+async fn lifecycle_transition_marks_dirty_disks_for_capacity_manager() {
+    let (disk_paths, ecstore) = setup_test_env().await;
+    let manager = create_isolated_manager(HybridStrategyConfig::default());
+    let _ = manager.get_dirty_disks().await;
+
+    let tier_name = format!("COLDTIER{}", &Uuid::new_v4().simple().to_string()[..8]).to_uppercase();
+    let _backend = register_mock_tier(&tier_name).await;
+
+    let bucket = format!("test-capacity-transition-{}", &Uuid::new_v4().simple().to_string()[..8]);
+    let object = "test/object.txt";
+    let payload = b"transition should mark dirty scope";
+
+    create_test_bucket(&ecstore, bucket.as_str()).await;
+    set_bucket_lifecycle_transition_with_tier(bucket.as_str(), &tier_name)
+        .await
+        .expect("Failed to set lifecycle configuration");
+    let _ = upload_test_object(&ecstore, bucket.as_str(), object, payload).await;
+
+    rustfs_ecstore::bucket::lifecycle::bucket_lifecycle_ops::enqueue_transition_for_existing_objects(
+        ecstore.clone(),
+        bucket.as_str(),
+    )
+    .await
+    .expect("Failed to enqueue transitioned object");
+
+    let _ = wait_for_transition(&ecstore, bucket.as_str(), object, TRANSITION_WAIT_TIMEOUT)
+        .await
+        .expect("object should transition before dirty scope assertion");
+
+    let dirty_disks = manager.get_dirty_disks().await;
+    assert_eq!(dirty_disks.len(), disk_paths.len());
+
+    let actual_paths: std::collections::HashSet<_> = dirty_disks
+        .into_iter()
+        .map(|disk| stdfs::canonicalize(&disk.drive_path).unwrap().to_string_lossy().into_owned())
+        .collect();
+    let expected_paths: std::collections::HashSet<_> = disk_paths
+        .iter()
+        .map(|path| stdfs::canonicalize(path).unwrap().to_string_lossy().into_owned())
+        .collect();
+    assert_eq!(actual_paths, expected_paths);
+}
diff --git a/rustfs/src/app/mod.rs b/rustfs/src/app/mod.rs
index ab8391102..3084c1090 100644
--- a/rustfs/src/app/mod.rs
+++ b/rustfs/src/app/mod.rs
@@ -21,5 +21,7 @@ pub mod context;
 pub mod multipart_usecase;
 pub mod object_usecase;
 
+#[cfg(test)]
+mod capacity_dirty_scope_test;
 #[cfg(test)]
 mod lifecycle_transition_api_test;
diff --git a/rustfs/src/app/multipart_usecase.rs b/rustfs/src/app/multipart_usecase.rs
index 16fc92990..8daab532c 100644
--- a/rustfs/src/app/multipart_usecase.rs
+++ b/rustfs/src/app/multipart_usecase.rs
@@ -16,6 +16,7 @@
 
 use crate::app::context::{AppContext, get_global_app_context};
 use crate::app::object_usecase::{build_put_like_object_lock_metadata, validate_existing_object_lock_for_write};
+use crate::capacity::record_capacity_write;
 use crate::error::ApiError;
 use crate::storage::access::has_bypass_governance_header;
 use crate::storage::entity;
@@ -66,6 +67,7 @@ use tokio::sync::RwLock;
 use tokio_util::io::StreamReader;
 use tracing::{info, instrument, warn};
 use urlencoding::encode;
+use uuid::Uuid;
 
 async fn maybe_enqueue_transition_immediate(obj_info: &rustfs_ecstore::store_api::ObjectInfo, src: LcEventSrc) {
     enqueue_transition_immediate(obj_info, src).await;
@@ -286,7 +288,9 @@ impl DefaultMultipartUsecase {
 
         let Some(multipart_upload) = multipart_upload else { return Err(s3_error!(InvalidPart)) };
 
-        let opts = &get_complete_multipart_upload_opts(&req.headers).map_err(ApiError::from)?;
+        let mut opts = get_complete_multipart_upload_opts(&req.headers).map_err(ApiError::from)?;
+        let capacity_scope_token = Uuid::new_v4();
+        opts.capacity_scope_token = Some(capacity_scope_token);
 
         let uploaded_parts_vec = multipart_upload
             .parts
@@ -360,9 +364,10 @@ impl DefaultMultipartUsecase {
 
         let obj_info = store
             .clone()
-            .complete_multipart_upload(&bucket, &key, &upload_id, uploaded_parts, opts)
+            .complete_multipart_upload(&bucket, &key, &upload_id, uploaded_parts, &opts)
             .await
             .map_err(ApiError::from)?;
+        record_capacity_write(Some(capacity_scope_token)).await;
 
         // check quota after completing multipart upload
         if let Some(metadata_sys) = self.bucket_metadata_sys() {
@@ -1056,7 +1061,7 @@ impl DefaultMultipartUsecase {
         let mut src_opts = copy_src_opts(&src_bucket, &src_key, &req.headers).map_err(ApiError::from)?;
         src_opts.version_id = src_version_id.clone();
 
-        let h = http::HeaderMap::new();
+        let h = HeaderMap::new();
         let get_opts = ObjectOptions {
             version_id: src_opts.version_id.clone(),
             versioned: src_opts.versioned,
@@ -1108,7 +1113,7 @@ impl DefaultMultipartUsecase {
             (0, src_info.size)
         };
 
-        let h = http::HeaderMap::new();
+        let h = HeaderMap::new();
         let get_opts = ObjectOptions {
             version_id: src_opts.version_id.clone(),
             versioned: src_opts.versioned,
diff --git a/rustfs/src/app/object_usecase.rs b/rustfs/src/app/object_usecase.rs
index 3df36f1c4..71669260b 100644
--- a/rustfs/src/app/object_usecase.rs
+++ b/rustfs/src/app/object_usecase.rs
@@ -27,14 +27,14 @@ use self::get_object_flow::{GetObjectBootstrap, GetObjectFlowRuntime};
 use self::types::*;
 
 use crate::app::context::{AppContext, default_notify_interface, get_global_app_context};
-use crate::capacity::capacity_manager::get_capacity_manager;
+use crate::capacity::record_capacity_write;
 use crate::config::RustFSBufferConfig;
 use crate::error::ApiError;
 use crate::storage::access::{PostObjectRequestMarker, authorize_request, has_bypass_governance_header, req_info_mut};
 use crate::storage::concurrency::{GetObjectGuard, get_concurrency_manager};
 use crate::storage::ecfs::*;
 use crate::storage::head_prefix::{head_prefix_not_found_message, probe_prefix_has_children};
-use crate::storage::helper::OperationHelper;
+use crate::storage::helper::{OperationHelper, spawn_background};
 use crate::storage::options::{
     copy_dst_opts, copy_src_opts, del_opts, extract_metadata, extract_metadata_from_mime_with_object_name,
     filter_object_metadata, get_content_sha256_with_query, get_opts, normalize_content_encoding_for_storage, put_opts,
@@ -1020,9 +1020,9 @@ impl DefaultObjectUsecase {
 
         let request_id = req
             .extensions
-            .get::<crate::storage::request_context::RequestContext>()
+            .get::<request_context::RequestContext>()
             .map(|ctx| ctx.request_id.clone())
-            .unwrap_or_else(|| crate::storage::request_context::RequestContext::fallback().request_id);
+            .unwrap_or_else(|| request_context::RequestContext::fallback().request_id);
         let bootstrap = init_get_object_bootstrap(&req.input.bucket, &req.input.key, &request_id)?;
         let request_context = prepare_get_object_request_context(&req).await?;
         let base_buffer_size = self.base_buffer_size();
@@ -1848,6 +1848,7 @@ impl DefaultObjectUsecase {
 
         let version_cfg = BucketVersioningSys::get(&bucket).await.unwrap_or_default();
         let bypass_governance = has_bypass_governance_header(&req.headers);
+        let capacity_scope_token = Uuid::new_v4();
 
         #[derive(Default, Clone)]
         struct DeleteResult {
@@ -1970,6 +1971,7 @@ impl DefaultObjectUsecase {
                 object_to_delete.clone(),
                 ObjectOptions {
                     version_suspended: version_cfg.suspended(),
+                    capacity_scope_token: Some(capacity_scope_token),
                     ..Default::default()
                 },
             )
@@ -2076,7 +2078,7 @@ impl DefaultObjectUsecase {
             .as_ref()
             .map(|context| context.notify())
             .unwrap_or_else(default_notify_interface);
-        crate::storage::helper::spawn_background(async move {
+        spawn_background(async move {
             for res in delete_results {
                 if let Some(dobj) = res.delete_object {
                     let event_name = if dobj.delete_marker {
@@ -2108,8 +2110,7 @@ impl DefaultObjectUsecase {
         let result = Ok(S3Response::new(output));
         let _ = helper.complete(&result);
         // Record write operation for capacity management (inline to avoid per-request tokio::spawn overhead)
-        let manager = get_capacity_manager();
-        manager.record_write_operation().await;
+        record_capacity_write(Some(capacity_scope_token)).await;
         result
     }
 
@@ -2144,6 +2145,8 @@ impl DefaultObjectUsecase {
         let mut opts: ObjectOptions = del_opts(&bucket, &key, version_id, &req.headers, metadata)
             .await
             .map_err(ApiError::from)?;
+        let capacity_scope_token = Uuid::new_v4();
+        opts.capacity_scope_token = Some(capacity_scope_token);
         let force_delete = opts.delete_prefix;
 
         let lock_cfg = BucketObjectLockSys::get(&bucket).await;
@@ -2255,8 +2258,7 @@ impl DefaultObjectUsecase {
                 })
                 .version_id(String::new());
             let result = Ok(S3Response::with_status(DeleteObjectOutput::default(), StatusCode::NO_CONTENT));
-            let manager = get_capacity_manager();
-            manager.record_write_operation().await;
+            record_capacity_write(Some(capacity_scope_token)).await;
             let _ = helper.complete(&result);
             return result;
         }
@@ -2304,8 +2306,7 @@ impl DefaultObjectUsecase {
 
         let result = Ok(S3Response::new(output));
         // Record write operation for capacity management (inline to avoid per-request tokio::spawn overhead)
-        let manager = get_capacity_manager();
-        manager.record_write_operation().await;
+        record_capacity_write(Some(capacity_scope_token)).await;
         let _ = helper.complete(&result);
         result
     }
@@ -2860,7 +2861,7 @@ impl DefaultObjectUsecase {
         let rreq_clone = rreq.clone();
         let version_id_clone = version_id.clone();
 
-        crate::storage::request_context::spawn_traced(async move {
+        request_context::spawn_traced(async move {
             let opts = ObjectOptions {
                 transition: TransitionOptions {
                     restore_request: rreq_clone,
@@ -2953,7 +2954,7 @@ impl DefaultObjectUsecase {
 
         let (tx, rx) = mpsc::channel::<S3Result<SelectObjectContentEvent>>(2);
         let stream = ReceiverStream::new(rx);
-        crate::storage::request_context::spawn_traced(async move {
+        request_context::spawn_traced(async move {
             let _ = tx
                 .send(Ok(SelectObjectContentEvent::Cont(ContinuationEvent::default())))
                 .await;
diff --git a/rustfs/src/app/object_usecase/app_adapters.rs b/rustfs/src/app/object_usecase/app_adapters.rs
index a8156c486..268c10eb5 100644
--- a/rustfs/src/app/object_usecase/app_adapters.rs
+++ b/rustfs/src/app/object_usecase/app_adapters.rs
@@ -400,7 +400,7 @@ pub(super) fn complete_put_response(helper: OperationHelper, output: PutObjectOu
 #[allow(clippy::too_many_arguments)]
 pub(super) fn spawn_put_extract_notification(
     notify: Arc<dyn NotifyInterface>,
-    request_context: Option<crate::storage::request_context::RequestContext>,
+    request_context: Option<request_context::RequestContext>,
     bucket: String,
     req_params: HashMap<String, String>,
     version_id: String,
@@ -422,7 +422,7 @@ pub(super) fn spawn_put_extract_notification(
         user_agent,
     };
 
-    crate::storage::helper::spawn_background_with_context(request_context, async move {
+    helper::spawn_background_with_context(request_context, async move {
         notify.notify(event_args).await;
     });
 }
diff --git a/rustfs/src/app/object_usecase/put_object_extract.rs b/rustfs/src/app/object_usecase/put_object_extract.rs
index 8f89d3e80..697f03880 100644
--- a/rustfs/src/app/object_usecase/put_object_extract.rs
+++ b/rustfs/src/app/object_usecase/put_object_extract.rs
@@ -167,10 +167,7 @@ impl DefaultObjectUsecase {
         let host = get_request_host(&request_context.headers);
         let port = get_request_port(&request_context.headers);
         let user_agent = get_request_user_agent(&request_context.headers);
-        let tracing_context = request_context
-            .extensions
-            .get::<crate::storage::request_context::RequestContext>()
-            .cloned();
+        let tracing_context = request_context.extensions.get::<request_context::RequestContext>().cloned();
 
         while let Some(entry) = entries.next().await {
             let mut f = match entry {
@@ -299,7 +296,9 @@ impl DefaultObjectUsecase {
                 opts.user_defined.extend(encryption_metadata);
             }
             opts.user_defined.extend(metadata);
-            let mut reader = rustfs_ecstore::store_api::ChunkNativePutData::new(hrd);
+            let capacity_scope_token = Uuid::new_v4();
+            opts.capacity_scope_token = Some(capacity_scope_token);
+            let mut reader = ChunkNativePutData::new(hrd);
 
             let obj_info = match store.put_object(&bucket, &fpath, &mut reader, &opts).await {
                 Ok(info) => info,
@@ -311,6 +310,7 @@ impl DefaultObjectUsecase {
                     return Err(ApiError::from(e).into());
                 }
             };
+            record_capacity_write(Some(capacity_scope_token)).await;
 
             let e_tag = obj_info.etag.clone().map(|etag| to_s3s_etag(&etag));
 
diff --git a/rustfs/src/app/object_usecase/put_object_flow.rs b/rustfs/src/app/object_usecase/put_object_flow.rs
index d7cf9b436..9ae0e5a8d 100644
--- a/rustfs/src/app/object_usecase/put_object_flow.rs
+++ b/rustfs/src/app/object_usecase/put_object_flow.rs
@@ -32,7 +32,7 @@ const SLOW_PUT_PHASE_DEBUG_THRESHOLD_MS: u64 = 100;
 const SLOW_PUT_PHASE_WARN_THRESHOLD_MS: u64 = 1_000;
 const SLOW_PUT_PHASE_ERROR_THRESHOLD_MS: u64 = 5_000;
 
-fn resolved_checksum_bytes(checksums: &PutObjectChecksums) -> Option<bytes::Bytes> {
+fn resolved_checksum_bytes(checksums: &PutObjectChecksums) -> Option<Bytes> {
     [
         (rustfs_rio::ChecksumType::CRC32, checksums.crc32.as_deref()),
         (rustfs_rio::ChecksumType::CRC32C, checksums.crc32c.as_deref()),
@@ -117,7 +117,7 @@ fn log_put_flow_phase(
     bucket: &str,
     key: &str,
     phase: &str,
-    elapsed: std::time::Duration,
+    elapsed: Duration,
     object_size: i64,
     small_eager: bool,
     reduced_copy: bool,
@@ -159,11 +159,11 @@ impl PooledBufferReader {
     }
 }
 
-impl tokio::io::AsyncRead for PooledBufferReader {
+impl AsyncRead for PooledBufferReader {
     fn poll_read(
         mut self: std::pin::Pin<&mut Self>,
         _cx: &mut std::task::Context<'_>,
-        buf: &mut tokio::io::ReadBuf<'_>,
+        buf: &mut ReadBuf<'_>,
     ) -> std::task::Poll<std::io::Result<()>> {
         let remaining = &self.buffer[self.position..];
         if remaining.is_empty() {
@@ -199,7 +199,7 @@ impl HashReaderDetector for PooledBufferReader {}
 
 impl TryGetIndex for PooledBufferReader {}
 
-async fn read_small_put_body_eager<S, B, E>(body: S, size: i64, pool: std::sync::Arc<BytesPool>) -> S3Result<PooledBuffer>
+async fn read_small_put_body_eager<S, B, E>(body: S, size: i64, pool: Arc<BytesPool>) -> S3Result<PooledBuffer>
 where
     S: Stream<Item = Result<B, E>>,
     B: Buf,
@@ -243,7 +243,7 @@ where
 async fn build_small_put_eager_hash_stage<S, B, E>(
     body: S,
     size: i64,
-    pool: std::sync::Arc<BytesPool>,
+    pool: Arc<BytesPool>,
     hash_values: PutObjectLegacyHashValues,
     headers: &HeaderMap,
     trailing_headers: Option<s3s::TrailingHeaders>,
@@ -587,6 +587,8 @@ impl DefaultObjectUsecase {
 
         let mt2 = metadata.clone();
         opts.user_defined.extend(metadata);
+        let capacity_scope_token = Uuid::new_v4();
+        opts.capacity_scope_token = Some(capacity_scope_token);
 
         let repoptions =
             get_must_replicate_options(&mt2, "".to_string(), ReplicationStatusType::Empty, ReplicationType::Object, opts.clone());
@@ -689,8 +691,7 @@ impl DefaultObjectUsecase {
             ..Default::default()
         };
 
-        let manager = get_capacity_manager();
-        manager.record_write_operation().await;
+        record_capacity_write(Some(capacity_scope_token)).await;
 
         {
             let duration_ms = start_time.elapsed().as_millis() as f64;
diff --git a/rustfs/src/app/object_usecase/zero_copy_tests.rs b/rustfs/src/app/object_usecase/zero_copy_tests.rs
index 5d9dc4f99..3aa253bdf 100644
--- a/rustfs/src/app/object_usecase/zero_copy_tests.rs
+++ b/rustfs/src/app/object_usecase/zero_copy_tests.rs
@@ -85,7 +85,7 @@ async fn setup_direct_chunk_test_env() -> (Vec<PathBuf>, Arc<ECStore>) {
         .unwrap();
 
     let buckets_list = ecstore
-        .list_bucket(&rustfs_ecstore::store_api::BucketOptions {
+        .list_bucket(&BucketOptions {
             no_metadata: true,
             ..Default::default()
         })
@@ -151,7 +151,7 @@ async fn setup_direct_chunk_multi_disk_test_env() -> (Vec<PathBuf>, Arc<ECStore>
         .unwrap();
 
     let buckets_list = ecstore
-        .list_bucket(&rustfs_ecstore::store_api::BucketOptions {
+        .list_bucket(&BucketOptions {
             no_metadata: true,
             ..Default::default()
         })
@@ -212,7 +212,7 @@ async fn create_direct_chunk_test_multipart_object(
     parts
 }
 
-fn find_part_file(root: &std::path::Path, part_name: &str) -> Option<PathBuf> {
+fn find_part_file(root: &Path, part_name: &str) -> Option<PathBuf> {
     let entries = std::fs::read_dir(root).ok()?;
     for entry in entries.flatten() {
         let path = entry.path();
@@ -231,7 +231,7 @@ fn find_part_file(root: &std::path::Path, part_name: &str) -> Option<PathBuf> {
     None
 }
 
-fn find_part_files(root: &std::path::Path, part_name: &str, out: &mut Vec<PathBuf>) {
+fn find_part_files(root: &Path, part_name: &str, out: &mut Vec<PathBuf>) {
     let Ok(entries) = std::fs::read_dir(root) else {
         return;
     };
@@ -248,7 +248,7 @@ fn find_part_files(root: &std::path::Path, part_name: &str, out: &mut Vec<PathBu
     }
 }
 
-async fn remove_part_files(root: &std::path::Path, part_name: &str) -> Vec<(PathBuf, Vec<u8>)> {
+async fn remove_part_files(root: &Path, part_name: &str) -> Vec<(PathBuf, Vec<u8>)> {
     let mut paths = Vec::new();
     find_part_files(root, part_name, &mut paths);
 
diff --git a/rustfs/src/capacity/capacity_integration.rs b/rustfs/src/capacity/capacity_integration.rs
index 82dcffb29..e161736b7 100644
--- a/rustfs/src/capacity/capacity_integration.rs
+++ b/rustfs/src/capacity/capacity_integration.rs
@@ -14,71 +14,26 @@
 
 //! Capacity management integration for application startup
 
-use crate::capacity::capacity_manager::{DataSource, get_capacity_manager, start_background_task};
-use rustfs_ecstore::disk::DiskAPI;
-use rustfs_io_metrics::{record_capacity_cache_hit, record_capacity_cache_miss};
-use tracing::{info, warn};
+use crate::capacity::{get_cached_capacity_with_metrics, init_capacity_management_for_local_disks};
 
 /// Initialize capacity management system
 /// This should be called during application startup after local disks are initialized
 pub async fn init_capacity_management() {
-    info!("Initializing capacity management system...");
-
-    // Get all local disks
-    let disks = rustfs_ecstore::store::all_local_disk().await;
-
-    if disks.is_empty() {
-        warn!("No local disks found, capacity management will not run");
-        return;
-    }
-
-    info!("Found {} local disk(s)", disks.len());
-
-    // Convert DiskStore to Disk (for compatibility with capacity_manager)
-    let disk_refs: Vec<rustfs_madmin::Disk> = disks
-        .iter()
-        .map(|ds| rustfs_madmin::Disk {
-            endpoint: ds.endpoint().to_string(),
-            drive_path: ds.to_string(),
-            root_disk: true,
-            ..Default::default()
-        })
-        .collect();
-
-    // Start background update task
-    info!("Starting background capacity update task...");
-    start_background_task(disk_refs).await;
-
-    info!("Capacity management system initialized successfully");
+    init_capacity_management_for_local_disks().await;
 }
 
 /// Get capacity statistics with metrics
 #[allow(dead_code)]
 pub async fn get_capacity_with_metrics() -> Option<(u64, String)> {
-    let manager = get_capacity_manager();
-
-    // Check cache
-    if let Some(cached) = manager.get_capacity().await {
-        record_capacity_cache_hit();
-
-        let source = match cached.source {
-            DataSource::RealTime => "real-time",
-            DataSource::Scheduled => "scheduled",
-            DataSource::WriteTriggered => "write-triggered",
-            DataSource::Fallback => "fallback",
-        };
-
-        return Some((cached.total_used, source.to_string()));
-    }
-
-    record_capacity_cache_miss();
-    None
+    get_cached_capacity_with_metrics()
+        .await
+        .map(|(capacity, source)| (capacity, source.to_string()))
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::capacity::capacity_manager::{CapacityUpdate, DataSource, get_capacity_manager};
+    use rustfs_object_capacity::capacity_manager::{CapacityUpdate, DataSource, get_capacity_manager};
 
     #[tokio::test]
     async fn test_get_capacity_with_metrics() {
diff --git a/rustfs/src/capacity/capacity_manager_test.rs b/rustfs/src/capacity/capacity_manager_test.rs
deleted file mode 100644
index 33158b1f9..000000000
--- a/rustfs/src/capacity/capacity_manager_test.rs
+++ /dev/null
@@ -1,267 +0,0 @@
-// Copyright 2024 RustFS Team
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//! Comprehensive tests for Hybrid Capacity Manager
-
-#[cfg(test)]
-mod tests {
-    use crate::capacity::capacity_manager::{CapacityUpdate, DataSource, HybridCapacityManager, HybridStrategyConfig};
-    use serial_test::serial;
-    use std::sync::Arc;
-    use std::sync::atomic::{AtomicUsize, Ordering};
-    use std::time::Duration;
-    use tokio::time::sleep;
-
-    #[tokio::test]
-    #[serial]
-    async fn test_capacity_manager_initialization() {
-        let manager = HybridCapacityManager::from_env();
-        assert!(manager.get_capacity().await.is_none());
-    }
-
-    #[tokio::test]
-    async fn test_capacity_update_and_retrieval() {
-        let manager = HybridCapacityManager::from_env();
-
-        assert!(manager.get_capacity().await.is_none());
-
-        manager
-            .update_capacity(CapacityUpdate::exact(1000, 10), DataSource::RealTime)
-            .await;
-
-        let cached = manager.get_capacity().await;
-        assert!(cached.is_some());
-        let cached = cached.unwrap();
-        assert_eq!(cached.total_used, 1000);
-        assert_eq!(cached.file_count, 10);
-        assert_eq!(cached.source, DataSource::RealTime);
-        assert!(!cached.is_estimated);
-    }
-
-    #[tokio::test]
-    async fn test_write_operation_recording() {
-        let manager = HybridCapacityManager::from_env();
-
-        manager.record_write_operation().await;
-        manager.record_write_operation().await;
-        manager.record_write_operation().await;
-
-        let frequency = manager.get_write_frequency().await;
-        assert_eq!(frequency, 3);
-    }
-
-    #[tokio::test]
-    async fn test_fast_update_detection() {
-        let manager = HybridCapacityManager::from_env();
-
-        assert!(!manager.needs_fast_update().await);
-
-        manager
-            .update_capacity(CapacityUpdate::exact(1000, 1), DataSource::RealTime)
-            .await;
-
-        assert!(!manager.needs_fast_update().await);
-
-        manager.record_write_operation().await;
-        sleep(Duration::from_millis(100)).await;
-
-        let _needs_update = manager.needs_fast_update().await;
-    }
-
-    #[tokio::test]
-    async fn test_cache_age_tracking() {
-        let manager = HybridCapacityManager::from_env();
-
-        assert!(manager.get_cache_age().await.is_none());
-
-        manager
-            .update_capacity(CapacityUpdate::exact(1000, 1), DataSource::RealTime)
-            .await;
-
-        let age = manager.get_cache_age().await;
-        assert!(age.is_some());
-        let age = age.unwrap();
-        assert!(age < Duration::from_secs(1));
-
-        sleep(Duration::from_millis(100)).await;
-
-        let age = manager.get_cache_age().await.unwrap();
-        assert!(age >= Duration::from_millis(100));
-    }
-
-    #[tokio::test]
-    async fn test_data_source_tracking() {
-        let manager = HybridCapacityManager::from_env();
-
-        let sources = vec![
-            DataSource::RealTime,
-            DataSource::Scheduled,
-            DataSource::WriteTriggered,
-            DataSource::Fallback,
-        ];
-
-        for source in sources {
-            manager.update_capacity(CapacityUpdate::exact(1000, 1), source).await;
-            let cached = manager.get_capacity().await.unwrap();
-            assert_eq!(cached.source, source);
-        }
-    }
-
-    #[tokio::test]
-    async fn test_config_from_env() {
-        let config = HybridStrategyConfig::from_env();
-
-        assert_eq!(config.scheduled_update_interval, Duration::from_secs(120));
-        assert_eq!(config.write_trigger_delay, Duration::from_secs(5));
-        assert_eq!(config.write_frequency_threshold, 5);
-        assert_eq!(config.fast_update_threshold, Duration::from_secs(30));
-        assert!(config.enable_smart_update);
-        assert!(config.enable_write_trigger);
-    }
-
-    #[tokio::test]
-    async fn test_write_frequency_window() {
-        let manager = HybridCapacityManager::from_env();
-
-        for _ in 0..20 {
-            manager.record_write_operation().await;
-        }
-
-        let frequency = manager.get_write_frequency().await;
-        assert_eq!(frequency, 20);
-    }
-
-    #[tokio::test]
-    #[serial]
-    async fn test_concurrent_access() {
-        let manager = Arc::new(HybridCapacityManager::from_env());
-        let mut handles = vec![];
-
-        for i in 0..10 {
-            let mgr = manager.clone();
-            let handle = tokio::spawn(async move {
-                mgr.update_capacity(CapacityUpdate::exact(i as u64 * 100, i), DataSource::RealTime)
-                    .await;
-                mgr.record_write_operation().await;
-            });
-            handles.push(handle);
-        }
-
-        for handle in handles {
-            handle.await.unwrap();
-        }
-
-        let cached = manager.get_capacity().await;
-        assert!(cached.is_some());
-
-        let frequency = manager.get_write_frequency().await;
-        assert_eq!(frequency, 10);
-    }
-
-    #[tokio::test]
-    #[serial]
-    async fn test_performance_overhead() {
-        let manager = Arc::new(HybridCapacityManager::from_env());
-        let start = std::time::Instant::now();
-
-        for i in 0..1000 {
-            manager
-                .update_capacity(CapacityUpdate::exact(i as u64, i), DataSource::RealTime)
-                .await;
-            manager.record_write_operation().await;
-            let _ = manager.get_capacity().await;
-        }
-
-        let elapsed = start.elapsed();
-        assert!(elapsed < Duration::from_secs(1));
-
-        println!("1000 operations completed in {:?}", elapsed);
-    }
-
-    #[tokio::test]
-    async fn test_refresh_or_join_singleflight() {
-        let manager = Arc::new(HybridCapacityManager::from_env());
-        let calls = Arc::new(AtomicUsize::new(0));
-
-        let mgr1 = manager.clone();
-        let calls1 = calls.clone();
-        let first = tokio::spawn(async move {
-            mgr1.refresh_or_join(DataSource::Scheduled, move || async move {
-                calls1.fetch_add(1, Ordering::SeqCst);
-                sleep(Duration::from_millis(50)).await;
-                Ok(CapacityUpdate::exact(2048, 8))
-            })
-            .await
-        });
-
-        sleep(Duration::from_millis(10)).await;
-
-        let mgr2 = manager.clone();
-        let calls2 = calls.clone();
-        let second = tokio::spawn(async move {
-            mgr2.refresh_or_join(DataSource::WriteTriggered, move || async move {
-                calls2.fetch_add(1, Ordering::SeqCst);
-                Ok(CapacityUpdate::exact(4096, 16))
-            })
-            .await
-        });
-
-        let first = first.await.unwrap().unwrap();
-        let second = second.await.unwrap().unwrap();
-
-        assert_eq!(calls.load(Ordering::SeqCst), 1);
-        assert_eq!(first.total_used, 2048);
-        assert_eq!(second.total_used, 2048);
-        let cached = manager.get_capacity().await.unwrap();
-        assert_eq!(cached.total_used, 2048);
-        assert_eq!(cached.file_count, 8);
-    }
-
-    #[tokio::test]
-    async fn test_spawn_refresh_if_needed_deduplicates_background_refresh() {
-        let manager = Arc::new(HybridCapacityManager::from_env());
-        let calls = Arc::new(AtomicUsize::new(0));
-
-        let first_manager = manager.clone();
-        let first_calls = calls.clone();
-        let started = first_manager
-            .clone()
-            .spawn_refresh_if_needed(DataSource::Scheduled, move || async move {
-                first_calls.fetch_add(1, Ordering::SeqCst);
-                sleep(Duration::from_millis(50)).await;
-                Ok(CapacityUpdate::estimated(8192, 32))
-            })
-            .await;
-        assert!(started);
-
-        let second_manager = manager.clone();
-        let second_calls = calls.clone();
-        let started = second_manager
-            .clone()
-            .spawn_refresh_if_needed(DataSource::Scheduled, move || async move {
-                second_calls.fetch_add(1, Ordering::SeqCst);
-                Ok(CapacityUpdate::exact(1, 1))
-            })
-            .await;
-        assert!(!started);
-
-        sleep(Duration::from_millis(100)).await;
-
-        assert_eq!(calls.load(Ordering::SeqCst), 1);
-        assert!(!manager.refresh_in_progress().await);
-        let cached = manager.get_capacity().await.unwrap();
-        assert_eq!(cached.total_used, 8192);
-        assert!(cached.is_estimated);
-    }
-}
diff --git a/rustfs/src/capacity/mod.rs b/rustfs/src/capacity/mod.rs
index 10e0c7749..1bb9ae2aa 100644
--- a/rustfs/src/capacity/mod.rs
+++ b/rustfs/src/capacity/mod.rs
@@ -48,22 +48,11 @@
 //! Capacity metrics flow through the existing observability pipeline via the `metrics`
 //! crate and `rustfs-io-metrics`; this module does not expose a Prometheus HTTP endpoint.
 //!
-//! ## Testing
-//!
-//! For isolated tests, use `create_isolated_manager()` to create independent
-//! instances instead of the global singleton:
-//!
-//! ```ignore
-//! use crate::capacity::create_isolated_manager;
-//!
-//! let manager = create_isolated_manager(HybridStrategyConfig::default());
-//! // Test without affecting global state
-//! ```
-//!
 
 pub mod capacity_integration;
-pub mod capacity_manager;
-#[cfg(test)]
-mod capacity_manager_test;
-#[cfg(test)]
-mod write_trigger_test;
+pub mod service;
+
+pub use service::{
+    capacity_disk_ref, get_cached_capacity_with_metrics, init_capacity_management_for_local_disks, record_capacity_write,
+    refresh_or_join_admin_disks, resolve_admin_used_capacity, spawn_refresh_if_needed_admin_disks,
+};
diff --git a/rustfs/src/capacity/service.rs b/rustfs/src/capacity/service.rs
new file mode 100644
index 000000000..7d64d3173
--- /dev/null
+++ b/rustfs/src/capacity/service.rs
@@ -0,0 +1,238 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use rustfs_ecstore::disk::DiskAPI;
+use rustfs_io_metrics::capacity_metrics::{
+    record_capacity_cache_hit, record_capacity_cache_miss, record_capacity_cache_served, record_capacity_refresh_request,
+    record_capacity_scan_mode,
+};
+use rustfs_object_capacity::{CapacityDiskRef, capacity_manager, scan};
+use std::sync::Arc;
+use std::time::Instant;
+use tracing::{debug, info, warn};
+
+pub fn capacity_disk_ref(endpoint: impl Into<String>, drive_path: impl Into<String>) -> CapacityDiskRef {
+    CapacityDiskRef {
+        endpoint: endpoint.into(),
+        drive_path: drive_path.into(),
+    }
+}
+
+fn capacity_disk_refs(disks: &[rustfs_madmin::Disk]) -> Vec<CapacityDiskRef> {
+    disks
+        .iter()
+        .map(|disk| capacity_disk_ref(disk.endpoint.clone(), disk.drive_path.clone()))
+        .collect()
+}
+
+async fn refresh_admin_disks_with_subset_fallback(
+    capacity_manager: &capacity_manager::HybridCapacityManager,
+    all_disks: Vec<CapacityDiskRef>,
+    allow_dirty_subset: bool,
+) -> Result<capacity_manager::CapacityUpdate, String> {
+    let (refresh_disks, dirty_subset) = if allow_dirty_subset {
+        scan::select_capacity_refresh_disks(capacity_manager, &all_disks).await
+    } else {
+        (all_disks.clone(), false)
+    };
+
+    match scan::refresh_capacity_with_scope(refresh_disks.clone(), dirty_subset).await {
+        Ok(update) => Ok(update),
+        Err(err) if dirty_subset => {
+            warn!("Dirty-subset capacity refresh failed: {}. Retrying full-disk refresh for recovery", err);
+            scan::refresh_capacity_with_scope(all_disks, false).await
+        }
+        Err(err) => Err(err),
+    }
+}
+
+pub async fn refresh_or_join_admin_disks(
+    capacity_manager: Arc<capacity_manager::HybridCapacityManager>,
+    source: capacity_manager::DataSource,
+    disks: &[rustfs_madmin::Disk],
+    allow_dirty_subset: bool,
+) -> Result<capacity_manager::CapacityUpdate, String> {
+    let all_disks = capacity_disk_refs(disks);
+    let refresh_manager = capacity_manager.clone();
+
+    capacity_manager
+        .refresh_or_join(source, move || {
+            let capacity_manager = refresh_manager.clone();
+            let all_disks = all_disks.clone();
+            async move {
+                refresh_admin_disks_with_subset_fallback(capacity_manager.as_ref(), all_disks, allow_dirty_subset).await
+            }
+        })
+        .await
+}
+
+pub async fn spawn_refresh_if_needed_admin_disks(
+    capacity_manager: Arc<capacity_manager::HybridCapacityManager>,
+    source: capacity_manager::DataSource,
+    disks: &[rustfs_madmin::Disk],
+    allow_dirty_subset: bool,
+) -> bool {
+    let all_disks = capacity_disk_refs(disks);
+    let refresh_manager = capacity_manager.clone();
+
+    capacity_manager
+        .spawn_refresh_if_needed(source, move || async move {
+            refresh_admin_disks_with_subset_fallback(refresh_manager.as_ref(), all_disks, allow_dirty_subset).await
+        })
+        .await
+}
+
+pub async fn record_capacity_write(scope_token: Option<uuid::Uuid>) {
+    capacity_manager::get_capacity_manager()
+        .record_write_operation_with_scope_token(scope_token)
+        .await;
+}
+
+pub async fn resolve_admin_used_capacity(disks: &[rustfs_madmin::Disk], fallback_used_capacity: u64) -> u64 {
+    let capacity_manager = capacity_manager::get_capacity_manager();
+
+    if let Some(cached) = capacity_manager.get_capacity().await {
+        record_capacity_cache_hit();
+        let cache_age = cached.last_update.elapsed();
+        let fast_update_threshold = capacity_manager.get_config().fast_update_threshold;
+
+        if cache_age < fast_update_threshold {
+            record_capacity_cache_served("fresh");
+            debug!(
+                "Using cached capacity: {} bytes (age: {:?}, source: {:?}, files={}, estimated={})",
+                cached.total_used, cache_age, cached.source, cached.file_count, cached.is_estimated
+            );
+            return cached.total_used;
+        }
+
+        let needs_update = capacity_manager.needs_fast_update().await;
+        let should_block = capacity_manager.should_block_on_refresh(cache_age);
+
+        if needs_update && should_block {
+            let start = Instant::now();
+            record_capacity_refresh_request("blocking", capacity_manager::DataSource::WriteTriggered.as_metric_label());
+            return match refresh_or_join_admin_disks(
+                capacity_manager.clone(),
+                capacity_manager::DataSource::WriteTriggered,
+                disks,
+                true,
+            )
+            .await
+            {
+                Ok(update) => {
+                    let elapsed = start.elapsed();
+                    debug!(
+                        "Foreground capacity refresh completed in {:?} (files={}, estimated={})",
+                        elapsed, update.file_count, update.is_estimated
+                    );
+                    update.total_used
+                }
+                Err(err) => {
+                    warn!("Foreground capacity refresh failed: {}, using cached value", err);
+                    record_capacity_cache_served("stale");
+                    cached.total_used
+                }
+            };
+        }
+
+        record_capacity_cache_served("stale");
+        debug!(
+            "Using stale cached capacity: {} bytes (age: {:?}, source: {:?}, files={}, estimated={}, needs_update={}, blocking={})",
+            cached.total_used, cache_age, cached.source, cached.file_count, cached.is_estimated, needs_update, should_block
+        );
+
+        record_capacity_refresh_request("background", capacity_manager::DataSource::Scheduled.as_metric_label());
+        if spawn_refresh_if_needed_admin_disks(capacity_manager.clone(), capacity_manager::DataSource::Scheduled, disks, true)
+            .await
+        {
+            debug!("Background capacity update started");
+        } else {
+            debug!("Background update already in progress, skipping spawn");
+        }
+
+        return cached.total_used;
+    }
+
+    let start = Instant::now();
+    record_capacity_cache_miss();
+    record_capacity_refresh_request("initial", capacity_manager::DataSource::RealTime.as_metric_label());
+    match refresh_or_join_admin_disks(capacity_manager.clone(), capacity_manager::DataSource::RealTime, disks, false).await {
+        Ok(update) => {
+            let elapsed = start.elapsed();
+            info!(
+                "Initial capacity calculation completed: {} bytes in {:?} (files={}, estimated={})",
+                update.total_used, elapsed, update.file_count, update.is_estimated
+            );
+            update.total_used
+        }
+        Err(err) => {
+            warn!(
+                "Failed to calculate data directory used capacity: {}, falling back to disk used capacity",
+                err
+            );
+            record_capacity_cache_served("fallback");
+            record_capacity_scan_mode("fallback");
+            capacity_manager
+                .update_capacity(
+                    capacity_manager::CapacityUpdate::fallback(fallback_used_capacity),
+                    capacity_manager::DataSource::Fallback,
+                )
+                .await;
+            fallback_used_capacity
+        }
+    }
+}
+
+pub async fn init_capacity_management_for_local_disks() {
+    info!("Initializing capacity management system...");
+
+    let disks = rustfs_ecstore::store::all_local_disk().await;
+    if disks.is_empty() {
+        warn!("No local disks found, capacity management will not run");
+        return;
+    }
+
+    info!("Found {} local disk(s)", disks.len());
+
+    let disk_refs = disks
+        .iter()
+        .map(|ds| capacity_disk_ref(ds.endpoint().to_string(), ds.to_string()))
+        .collect();
+
+    info!("Starting background capacity update task...");
+    capacity_manager::start_background_task(disk_refs).await;
+
+    info!("Capacity management system initialized successfully");
+}
+
+pub async fn get_cached_capacity_with_metrics() -> Option<(u64, &'static str)> {
+    let manager = capacity_manager::get_capacity_manager();
+
+    if let Some(cached) = manager.get_capacity().await {
+        record_capacity_cache_hit();
+        return Some((cached.total_used, capacity_source_label(cached.source)));
+    }
+
+    record_capacity_cache_miss();
+    None
+}
+
+fn capacity_source_label(source: capacity_manager::DataSource) -> &'static str {
+    match source {
+        capacity_manager::DataSource::RealTime => "real-time",
+        capacity_manager::DataSource::Scheduled => "scheduled",
+        capacity_manager::DataSource::WriteTriggered => "write-triggered",
+        capacity_manager::DataSource::Fallback => "fallback",
+    }
+}
diff --git a/rustfs/src/capacity/write_trigger_test.rs b/rustfs/src/capacity/write_trigger_test.rs
deleted file mode 100644
index 1a606e005..000000000
--- a/rustfs/src/capacity/write_trigger_test.rs
+++ /dev/null
@@ -1,87 +0,0 @@
-// Copyright 2024 RustFS Team
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//! Write trigger integration tests
-
-#[cfg(test)]
-mod tests {
-    use crate::capacity::capacity_manager::{CapacityUpdate, DataSource, HybridCapacityManager};
-    use serial_test::serial;
-    use std::time::Duration;
-
-    #[tokio::test]
-    #[serial]
-    async fn test_write_trigger_integration() {
-        let manager = HybridCapacityManager::from_env();
-
-        manager.record_write_operation().await;
-        manager.record_write_operation().await;
-        manager.record_write_operation().await;
-
-        let frequency = manager.get_write_frequency().await;
-        assert_eq!(frequency, 3);
-    }
-
-    #[tokio::test]
-    #[serial]
-    async fn test_write_trigger_with_capacity_update() {
-        let manager = HybridCapacityManager::from_env();
-
-        manager
-            .update_capacity(CapacityUpdate::exact(1000, 4), DataSource::WriteTriggered)
-            .await;
-
-        let cached = manager.get_capacity().await;
-        assert!(cached.is_some());
-        let cached = cached.unwrap();
-        assert_eq!(cached.total_used, 1000);
-        assert_eq!(cached.file_count, 4);
-        assert_eq!(cached.source, DataSource::WriteTriggered);
-    }
-
-    #[tokio::test]
-    async fn test_write_frequency_tracking() {
-        let manager = HybridCapacityManager::from_env();
-
-        assert_eq!(manager.get_write_frequency().await, 0);
-
-        for _ in 0..5 {
-            manager.record_write_operation().await;
-        }
-
-        assert_eq!(manager.get_write_frequency().await, 5);
-
-        tokio::time::sleep(Duration::from_millis(10)).await;
-        assert_eq!(manager.get_write_frequency().await, 5);
-    }
-
-    #[tokio::test]
-    async fn test_needs_fast_update() {
-        let manager = HybridCapacityManager::from_env();
-
-        assert!(!manager.needs_fast_update().await);
-
-        manager
-            .update_capacity(CapacityUpdate::exact(1000, 1), DataSource::Scheduled)
-            .await;
-
-        assert!(!manager.needs_fast_update().await);
-
-        manager.record_write_operation().await;
-
-        let needs_update = manager.needs_fast_update().await;
-        #[allow(clippy::overly_complex_bool_expr)]
-        let _ = needs_update || !needs_update;
-    }
-}