diff --git a/Cargo.lock b/Cargo.lock
index fafbc34ba..ba722d3d5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -9565,6 +9565,7 @@ dependencies = [
 name = "rustfs-ecstore"
 version = "1.0.0-rc.3"
 dependencies = [
+ "ahash",
  "arc-swap",
  "async-channel",
  "async-recursion",
diff --git a/crates/ecstore/Cargo.toml b/crates/ecstore/Cargo.toml
index fb223489c..e56d6cffb 100644
--- a/crates/ecstore/Cargo.toml
+++ b/crates/ecstore/Cargo.toml
@@ -235,6 +235,9 @@ faster-hex = { workspace = true }
 ratelimit = { workspace = true }
 aws-smithy-http-client = { workspace = true, default-features = false, features = ["rustls-aws-lc"] }
 
+# High-performance hashing
+ahash = { workspace = true, features = ["serde"] }
+
 # Observability and Metrics
 metrics = { workspace = true }
 
diff --git a/crates/ecstore/src/bucket/lifecycle/bucket_lifecycle_ops.rs b/crates/ecstore/src/bucket/lifecycle/bucket_lifecycle_ops.rs
index 5e13ba918..0a6ab0746 100644
--- a/crates/ecstore/src/bucket/lifecycle/bucket_lifecycle_ops.rs
+++ b/crates/ecstore/src/bucket/lifecycle/bucket_lifecycle_ops.rs
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use ahash::AHashMap;
 use super::{metadata_boundary, object_lock_boundary, runtime_boundary as runtime_sources};
 use crate::bucket::lifecycle::bucket_lifecycle_audit::{
     LcAuditEvent, LcEventSrc, emit_non_transitioned_expiration_event, emit_transition_complete_event,
@@ -2870,7 +2871,7 @@ fn spawn_transition_transaction_recovery_once(api: Arc<ECStore>) {
 struct StaleMultipartUploadCandidate {
     path: String,
     initiated: OffsetDateTime,
-    metadata: Option<HashMap<String, String>>,
+    metadata: Option<AHashMap<String, String>>,
 }
 
 fn parse_stale_uploads_duration(env_key: &str, default: StdDuration) -> StdDuration {
@@ -2915,9 +2916,9 @@ async fn stale_upload_current_size(set: &Arc<SetDisks>, metadata: &HashMap<Strin
     stale_upload_current_size_with_opts(set, metadata, upload_dir, false).await
 }
 
-async fn stale_upload_current_size_with_opts(
+async fn stale_upload_current_size_with_opts<S: std::hash::BuildHasher>(
     set: &Arc<SetDisks>,
-    metadata: &HashMap<String, String>,
+    metadata: &HashMap<String, String, S>,
     upload_dir: &str,
     no_lock: bool,
 ) -> Option<usize> {
@@ -2950,9 +2951,9 @@ async fn stale_upload_current_size_with_opts(
     )
 }
 
-async fn stale_upload_lifecycle_due(
+async fn stale_upload_lifecycle_due<S: std::hash::BuildHasher>(
     set: &Arc<SetDisks>,
-    metadata: &HashMap<String, String>,
+    metadata: &HashMap<String, String, S>,
     initiated: OffsetDateTime,
     upload_dir: &str,
     no_lock: bool,
@@ -2978,7 +2979,7 @@ async fn stale_upload_lifecycle_due(
             .unwrap_or_default(),
         is_latest: true,
         delete_marker: false,
-        user_defined: metadata.clone(),
+        user_defined: metadata.iter().map(|(k, v)| (k.clone(), v.clone())).collect(),
         ..Default::default()
     };
 
diff --git a/crates/ecstore/src/core/pools.rs b/crates/ecstore/src/core/pools.rs
index 0f188db18..2645b4912 100644
--- a/crates/ecstore/src/core/pools.rs
+++ b/crates/ecstore/src/core/pools.rs
@@ -5796,7 +5796,7 @@ fn decommission_remote_tiered_opts(
         versioned: version_id.is_some(),
         version_id,
         mod_time: version.mod_time,
-        user_defined: version.metadata.clone(),
+        user_defined: version.metadata.iter().map(|(k, v)| (k.clone(), v.clone())).collect(),
         src_pool_idx,
         data_movement: true,
         incl_free_versions: version.tier_free_version(),
diff --git a/crates/ecstore/src/object_api/types.rs b/crates/ecstore/src/object_api/types.rs
index d91d96a0d..ef7874ca6 100644
--- a/crates/ecstore/src/object_api/types.rs
+++ b/crates/ecstore/src/object_api/types.rs
@@ -1008,7 +1008,7 @@ impl ObjectInfo {
             successor_mod_time: fi.successor_mod_time,
             etag,
             inlined,
-            user_defined: Arc::new(metadata),
+            user_defined: Arc::new(metadata.iter().map(|(k, v)| (k.clone(), v.clone())).collect()),
             transitioned_object,
             transition_version_state: fi.transition_version_state,
             checksum: fi.checksum.clone(),
@@ -1316,7 +1316,7 @@ impl ObjectInfo {
         if part > 0
             && let Some(checksums) = self.parts.iter().find(|p| p.number == part).and_then(|p| p.checksums.clone())
         {
-            return Ok((checksums, true));
+            return Ok((checksums.iter().map(|(k, v)| (k.clone(), v.clone())).collect(), true));
         }
 
         if let Some(data) = &self.checksum {
diff --git a/crates/ecstore/src/services/rebalance/migration.rs b/crates/ecstore/src/services/rebalance/migration.rs
index cf2dabd8f..ee4d635f4 100644
--- a/crates/ecstore/src/services/rebalance/migration.rs
+++ b/crates/ecstore/src/services/rebalance/migration.rs
@@ -57,7 +57,7 @@ fn rebalance_remote_tiered_opts(
         versioned: version_id.is_some(),
         version_id,
         mod_time: version.mod_time,
-        user_defined: version.metadata.clone(),
+        user_defined: version.metadata.iter().map(|(k, v)| (k.clone(), v.clone())).collect(),
         src_pool_idx,
         data_movement: true,
         include_part_checksums: true,
diff --git a/crates/ecstore/src/set_disk/ops/multipart.rs b/crates/ecstore/src/set_disk/ops/multipart.rs
index 2c25ebeb8..163f99e8b 100644
--- a/crates/ecstore/src/set_disk/ops/multipart.rs
+++ b/crates/ecstore/src/set_disk/ops/multipart.rs
@@ -1280,7 +1280,7 @@ impl crate::storage_api_contracts::multipart::MultipartOperations for SetDisks {
                 mod_time: Some(OffsetDateTime::now_utc()),
                 actual_size,
                 index: index_op,
-                checksums: if checksums.is_empty() { None } else { Some(checksums) },
+                checksums: if checksums.is_empty() { None } else { Some(checksums.iter().map(|(k, v)| (k.clone(), v.clone())).collect()) },
                 ..Default::default()
             };
 
@@ -1468,7 +1468,7 @@ impl crate::storage_api_contracts::multipart::MultipartOperations for SetDisks {
             max_parts,
             part_number_marker,
             user_defined: {
-                let mut metadata = fi.metadata.clone();
+                let mut metadata: HashMap<String, String> = fi.metadata.iter().map(|(k, v)| (k.clone(), v.clone())).collect();
                 strip_internal_multipart_metadata(&mut metadata);
                 metadata
             },
@@ -1727,7 +1727,7 @@ impl crate::storage_api_contracts::multipart::MultipartOperations for SetDisks {
         let mod_time = opts.mod_time.unwrap_or_else(OffsetDateTime::now_utc);
 
         for f in parts_metadatas.iter_mut() {
-            f.metadata = user_defined.clone();
+            f.metadata = user_defined.iter().map(|(k, v)| (k.clone(), v.clone())).collect();
             f.mod_time = Some(mod_time);
             f.fresh = true;
         }
@@ -1816,7 +1816,7 @@ impl crate::storage_api_contracts::multipart::MultipartOperations for SetDisks {
             upload_id: upload_id.to_owned(),
             user_defined: {
                 strip_internal_multipart_metadata(&mut fi.metadata);
-                fi.metadata.clone()
+                fi.metadata.iter().map(|(k, v)| (k.clone(), v.clone())).collect()
             },
             ..Default::default()
         })
diff --git a/crates/ecstore/src/set_disk/ops/object.rs b/crates/ecstore/src/set_disk/ops/object.rs
index 594814257..30be81498 100644
--- a/crates/ecstore/src/set_disk/ops/object.rs
+++ b/crates/ecstore/src/set_disk/ops/object.rs
@@ -19,6 +19,7 @@
 //! bounds are unchanged, and the impls reach shared primitives through the
 //! SetDisks core (io_primitives) via inherent calls.
 
+use ahash::AHashMap;
 use super::super::*;
 use super::bitrot_self_verify::{BitrotSelfVerifyTarget, drop_failed_writer_disks, verify_written_bitrot_shards};
 use crate::bucket::utils::is_meta_bucketname;
@@ -2697,7 +2698,7 @@ impl SetDisks {
                 )));
             }
 
-            fi.metadata = user_defined.into();
+            fi.metadata = user_defined.iter().map(|(k, v)| (k.clone(), v.clone())).collect();
             fi.mod_time = mod_time;
             fi.size = w_size as i64;
             fi.versioned = opts.versioned || opts.version_suspended;
@@ -5882,7 +5883,7 @@ impl crate::storage_api_contracts::object::ObjectOperations for SetDisks {
         } else {
             None
         };
-        let mut replacement_metadata: AHashMap<String, String> = (*src_info.user_defined).clone().into();
+        let mut replacement_metadata: AHashMap<String, String> = (*src_info.user_defined).iter().map(|(k, v)| (k.clone(), v.clone())).collect();
         if let Some(part_checksums) = preserved_part_checksums {
             rustfs_utils::http::insert_str(&mut replacement_metadata, rustfs_utils::http::SUFFIX_PART_CHECKSUMS, part_checksums);
         }