fix(replication): bin transfer summaries at 128 MiB and keep window refresh off the hot path

Second review round:

- update_xfer_rate split at 1 MiB while the minio-go transferSummary
  labels (and RustFS's own worker-pool split) mean >= 128 MiB for
  Large, so a 2 MiB replication reported under Large with Small stuck
  at zero. The producer now bins on MIN_LARGE_OBJ_SIZE; a MetricsV2
  assertion covers 2 MiB / 127 MiB / exactly 128 MiB.
- add_size no longer recomputes the rolling windows: two full
  one-hour-deque scans per failure under the bucket-stats write lock
  made failure bursts quadratic (30k events ~2.1s). The windows are
  stamped only at the collection point (get_latest_replication_stats,
  which serves both the local leg and the peer RPC); the aggregation
  regression now drives that path explicitly before the RPC round trip
  and merge.

crates/ecstore/src/api/mod.rs

@@ -184,17 +184,18 @@ pub mod bucket {
             mrf_backlog_observability_snapshot,
         };
         pub use crate::bucket::replication::{
-            BucketReplicationResyncStatus, BucketReplicationStats, BucketStats, DeleteReplicationConfigSnapshot,
-            DeletedObjectReplicationInfo, DurableMrfBacklog, DynReplicationPool, MrfOpKind, MrfReplicateEntry,
-            MustReplicateOptions, ObjectOpts, REMOTE_TARGET_CAPABILITY_CONTRACT_VERSION, REMOTE_TARGET_UNSUPPORTED_FIELDS,
-            REMOTE_TARGET_WRITABLE_FIELDS, REPLICATE_INCOMING_DELETE, REPLICATION_CAPABILITY_CONTRACT_VERSION,
-            REPLICATION_READ_ONLY_HISTORICAL_FIELDS, REPLICATION_WRITABLE_FIELDS, ReplicateDecision, ReplicateObjectInfo,
-            ReplicationBatchAdmission, ReplicationConfig, ReplicationConfigStructureError, ReplicationConfigurationExt,
-            ReplicationDeleteScheduleInput, ReplicationDeleteStateSource, ReplicationHealQueueResult, ReplicationObjectBridge,
-            ReplicationObjectIO, ReplicationOperation, ReplicationPoolTrait, ReplicationPriority, ReplicationQueueAdmission,
-            ReplicationScannerBridge, ReplicationState, ReplicationStats, ReplicationStatusType, ReplicationStorage,
-            ReplicationTargetValidationError, ReplicationType, ResyncOpts, ResyncStatusType, RuntimeReplicationTargetBacklog,
-            TargetReplicationResyncStatus, VersionPurgeStatusType, commit_force_delete_intent, complete_force_delete_intent,
+            BucketReplicationResyncStatus, BucketReplicationStat, BucketReplicationStats, BucketStats,
+            DeleteReplicationConfigSnapshot, DeletedObjectReplicationInfo, DurableMrfBacklog, DynReplicationPool, InQueueMetric,
+            MrfOpKind, MrfReplicateEntry, MustReplicateOptions, ObjectOpts, REMOTE_TARGET_CAPABILITY_CONTRACT_VERSION,
+            REMOTE_TARGET_UNSUPPORTED_FIELDS, REMOTE_TARGET_WRITABLE_FIELDS, REPLICATE_INCOMING_DELETE,
+            REPLICATION_CAPABILITY_CONTRACT_VERSION, REPLICATION_READ_ONLY_HISTORICAL_FIELDS, REPLICATION_WRITABLE_FIELDS,
+            ReplicateDecision, ReplicateObjectInfo, ReplicationBatchAdmission, ReplicationConfig,
+            ReplicationConfigStructureError, ReplicationConfigurationExt, ReplicationDeleteScheduleInput,
+            ReplicationDeleteStateSource, ReplicationHealQueueResult, ReplicationObjectBridge, ReplicationObjectIO,
+            ReplicationOperation, ReplicationPoolTrait, ReplicationPriority, ReplicationQueueAdmission, ReplicationScannerBridge,
+            ReplicationState, ReplicationStats, ReplicationStatusType, ReplicationStorage, ReplicationTargetValidationError,
+            ReplicationType, ResyncOpts, ResyncStatusType, RuntimeReplicationTargetBacklog, TargetReplicationResyncStatus,
+            VersionPurgeStatusType, XferStats, commit_force_delete_intent, complete_force_delete_intent,
             delete_replication_state_from_config, delete_replication_version_id, get_global_replication_pool,
             get_global_replication_stats, init_background_replication, invalid_replication_config_status_field,
             persist_force_delete_intent, read_durable_mrf_backlog, replication_state_to_filemeta, replication_status_to_filemeta,

crates/ecstore/src/bucket/replication/mod.rs

@@ -81,6 +81,6 @@ pub use replication_queue_boundary::{
 pub use replication_resync_boundary::{BucketReplicationResyncStatus, ResyncOpts, TargetReplicationResyncStatus};
 pub use replication_scanner_bridge::ReplicationScannerBridge;
 pub use replication_state::{ReplicationStats, RuntimeReplicationTargetBacklog};
-pub use replication_stats_boundary::{BucketReplicationStats, BucketStats};
+pub use replication_stats_boundary::{BucketReplicationStat, BucketReplicationStats, BucketStats, InQueueMetric, XferStats};
 pub use replication_storage_boundary::{ReplicationObjectIO, ReplicationStorage};
 pub(crate) use replication_target_config_bridge::ReplicationTargetConfigBridge;

crates/ecstore/src/bucket/replication/replication_state.rs

@@ -704,6 +704,12 @@ impl ReplicationStats {
         } else {
             BucketReplicationStats::new()
         };
+        // Stamp the serializable failure windows from the live samples: the
+        // samples themselves do not cross the peer-RPC wire, so this snapshot
+        // is what cluster aggregation and the metrics endpoints see.
+        for stat in replication_stats.stats.values_mut() {
+            stat.fail_stats.refresh_windows();
+        }
         let uptime = if cache.contains_key(bucket) {
             SystemTime::now()
                 .duration_since(SystemTime::UNIX_EPOCH)

crates/ecstore/src/bucket/replication/replication_stats_boundary.rs

@@ -15,7 +15,9 @@
 #[cfg(test)]
 pub(crate) use rustfs_replication::FailStats;
 pub(crate) use rustfs_replication::{
-    ActiveWorkerStat, BucketReplicationStat, InQueueMetric, ProxyMetric, ProxyStatsCache, QueueCache, ReplicationMetricScope,
-    SRMetricsSummary, XferStats,
+    ActiveWorkerStat, ProxyMetric, ProxyStatsCache, QueueCache, ReplicationMetricScope, SRMetricsSummary,
 };
-pub use rustfs_replication::{BucketReplicationStats, BucketStats};
+// Public so the admin wire DTOs (rustfs/src/admin/replication_metrics_wire.rs)
+// can project the internal stats onto the minio-go response shapes through
+// the storage_api facade chain.
+pub use rustfs_replication::{BucketReplicationStat, BucketReplicationStats, BucketStats, InQueueMetric, XferStats};

crates/replication/src/stats.rs

@@ -520,6 +520,14 @@ struct FailureSample {
 pub struct FailStats {
     pub count: i64,
     pub size: i64,
+    /// Rolling-window snapshots refreshed at collection time
+    /// ([`Self::refresh_windows`]). The raw samples (`recent`) are process
+    /// local (serde-skipped), so these fields are what survives the peer-RPC
+    /// wire and [`Self::merge`]-based cluster aggregation.
+    #[serde(default)]
+    pub last_minute: FailedMetric,
+    #[serde(default)]
+    pub last_hour: FailedMetric,
     #[serde(skip)]
     recent: VecDeque<FailureSample>,
 }
@@ -537,6 +545,17 @@ impl FailStats {
         self.prune(observed_at);
     }
 
+    /// Recompute the serializable rolling-window snapshots from the local
+    /// samples. Called at the collection point (per-node stats snapshot),
+    /// never on the failure hot path — the two deque scans are O(window) and
+    /// `add_size` runs under the bucket-stats write lock. Only meaningful on
+    /// the live per-node struct: a deserialized or merged struct has no
+    /// samples, and refreshing it would wipe the aggregated windows.
+    pub fn refresh_windows(&mut self) {
+        self.last_minute = self.recent_since(Duration::from_secs(60));
+        self.last_hour = self.recent_since(Duration::from_secs(3600));
+    }
+
     fn prune(&mut self, observed_at: Instant) {
         while self
             .recent
@@ -565,6 +584,16 @@ impl FailStats {
         Self {
             count: self.count.saturating_add(other.count),
             size: self.size.saturating_add(other.size),
+            // The window snapshots sum across nodes; the raw samples do not
+            // travel and stay empty on aggregated structs.
+            last_minute: FailedMetric {
+                count: self.last_minute.count.saturating_add(other.last_minute.count),
+                size: self.last_minute.size.saturating_add(other.last_minute.size),
+            },
+            last_hour: FailedMetric {
+                count: self.last_hour.count.saturating_add(other.last_hour.count),
+                size: self.last_hour.size.saturating_add(other.last_hour.size),
+            },
             recent: VecDeque::new(),
         }
     }
@@ -636,7 +665,9 @@ impl BucketReplicationStat {
     }
 
     pub fn update_xfer_rate(&mut self, size: i64, duration: Duration) {
-        if size > 1024 * 1024 {
+        // Same boundary as the worker-pool split and minio-go's
+        // Large/Small transfer-summary labels: >= 128 MiB is "large".
+        if size >= crate::runtime::MIN_LARGE_OBJ_SIZE {
             self.xfer_rate_lrg.add_size(size, duration);
         } else {
             self.xfer_rate_sml.add_size(size, duration);

rustfs/src/admin/handlers/replication.rs

@@ -535,8 +535,13 @@ impl Operation for GetReplicationMetricsHandler {
 
         let bucket_stats = cluster_replication_stats(bucket, app_context_from_req(&req)).await;
 
-        let data = serde_json::to_vec(&bucket_stats.replication_stats)
-            .map_err(|_| S3Error::with_message(S3ErrorCode::InternalError, "serialize failed"))?;
+        // Same minio-go `replication.Metrics` wire shape as
+        // `?replication-metrics` — the internal snake_case stats are the peer
+        // RPC wire format and must not leak here.
+        let data = serde_json::to_vec(&crate::admin::replication_metrics_wire::MetricsWire::from(
+            &bucket_stats.replication_stats,
+        ))
+        .map_err(|_| S3Error::with_message(S3ErrorCode::InternalError, "serialize failed"))?;
         let mut headers = HeaderMap::new();
         headers.insert(CONTENT_TYPE, HeaderValue::from_static("application/json"));
         Ok(S3Response::with_headers((StatusCode::OK, Body::from(data)), headers))

rustfs/src/admin/mod.rs

@@ -17,6 +17,7 @@ mod auth;
 pub mod console;
 pub mod handlers;
 mod plugin_contract;
+pub(crate) mod replication_metrics_wire;
 // Contract inventory is validated by tests before later runtime integration.
 #[allow(dead_code)]
 pub(crate) mod route_policy;

rustfs/src/admin/replication_metrics_wire.rs

@@ -0,0 +1,597 @@
+// 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.
+
+//! Serialize-only wire projections of the internal replication statistics
+//! onto the minio-go `replication.Metrics` / `replication.MetricsV2` json
+//! shapes consumed by `mc replicate status` (`?replication-metrics[=2]` and
+//! the admin `replicationmetrics` endpoint).
+//!
+//! Red line: the internal `BucketStats` family in
+//! `crates/replication/src/stats.rs` is ALSO the intra-cluster peer-RPC wire
+//! format — `node_service.rs` encodes it with `rmp_serde::to_vec_named`, so
+//! its Rust field names travel between nodes as msgpack map keys. Renaming
+//! those serde names would break mixed-version clusters mid rolling upgrade.
+//! All madmin/minio-go interop therefore happens in these DTOs; never add
+//! `#[serde(rename)]` to the internal structs instead.
+//!
+//! Field names below are the exact json tags of minio-go
+//! `pkg/replication/replication.go` (v7.0.91). Keys minio-go does not know
+//! are RustFS extensions; Go decoders ignore unknown keys. `max`/`peak` are
+//! both emitted for the queue peak because the MinIO server writes `max`
+//! while minio-go reads `peak` (an upstream drift); emitting both keeps every
+//! decoder working.
+
+use serde::Serialize;
+use std::collections::HashMap;
+use std::time::Duration;
+
+use crate::admin::storage_api::replication::{
+    BucketReplicationStat as InternalReplicationStat, BucketReplicationStats as InternalReplicationStats, BucketStats,
+    InQueueMetric as InternalInQueueMetric, XferStats as InternalXferStats,
+};
+
+/// minio-go `replication.RStat`.
+#[derive(Debug, Default, Clone, Copy, Serialize)]
+pub(crate) struct RStatWire {
+    #[serde(rename = "count")]
+    pub count: f64,
+    #[serde(rename = "bytes")]
+    pub bytes: i64,
+}
+
+/// minio-go `replication.TimedErrStats`.
+#[derive(Debug, Default, Clone, Copy, Serialize)]
+pub(crate) struct TimedErrStatsWire {
+    #[serde(rename = "lastMinute")]
+    pub last_minute: RStatWire,
+    #[serde(rename = "lastHour")]
+    pub last_hour: RStatWire,
+    #[serde(rename = "totals")]
+    pub totals: RStatWire,
+}
+
+impl TimedErrStatsWire {
+    fn add(self, other: TimedErrStatsWire) -> TimedErrStatsWire {
+        fn add(a: RStatWire, b: RStatWire) -> RStatWire {
+            RStatWire {
+                count: a.count + b.count,
+                bytes: a.bytes.saturating_add(b.bytes),
+            }
+        }
+        TimedErrStatsWire {
+            last_minute: add(self.last_minute, other.last_minute),
+            last_hour: add(self.last_hour, other.last_hour),
+            totals: add(self.totals, other.totals),
+        }
+    }
+}
+
+/// minio-go `replication.QStat`.
+#[derive(Debug, Default, Clone, Copy, Serialize)]
+pub(crate) struct QStatWire {
+    #[serde(rename = "count")]
+    pub count: f64,
+    #[serde(rename = "bytes")]
+    pub bytes: f64,
+}
+
+/// minio-go `replication.InQueueMetric`, with the queue peak emitted under
+/// both `peak` (minio-go tag) and `max` (MinIO server tag).
+#[derive(Debug, Default, Clone, Copy, Serialize)]
+pub(crate) struct InQueueMetricWire {
+    #[serde(rename = "curr")]
+    pub curr: QStatWire,
+    #[serde(rename = "avg")]
+    pub avg: QStatWire,
+    #[serde(rename = "max")]
+    pub max: QStatWire,
+    #[serde(rename = "peak")]
+    pub peak: QStatWire,
+}
+
+impl From<&InternalInQueueMetric> for InQueueMetricWire {
+    fn from(metric: &InternalInQueueMetric) -> Self {
+        fn qstat(bytes: i64, count: i64) -> QStatWire {
+            QStatWire {
+                count: count as f64,
+                bytes: bytes as f64,
+            }
+        }
+        let peak = qstat(metric.max.bytes, metric.max.count);
+        InQueueMetricWire {
+            curr: qstat(metric.curr.bytes, metric.curr.count),
+            avg: qstat(metric.avg.bytes, metric.avg.count),
+            max: peak,
+            peak,
+        }
+    }
+}
+
+/// minio-go `replication.XferStats`.
+#[derive(Debug, Default, Clone, Copy, Serialize)]
+pub(crate) struct XferStatsWire {
+    #[serde(rename = "avgRate")]
+    pub avg_rate: f64,
+    #[serde(rename = "peakRate")]
+    pub peak_rate: f64,
+    #[serde(rename = "currRate")]
+    pub curr_rate: f64,
+}
+
+impl XferStatsWire {
+    fn merge(self, other: XferStatsWire) -> XferStatsWire {
+        XferStatsWire {
+            avg_rate: self.avg_rate + other.avg_rate,
+            peak_rate: self.peak_rate.max(other.peak_rate),
+            curr_rate: self.curr_rate + other.curr_rate,
+        }
+    }
+}
+
+impl From<&InternalXferStats> for XferStatsWire {
+    fn from(stats: &InternalXferStats) -> Self {
+        XferStatsWire {
+            avg_rate: stats.avg,
+            peak_rate: stats.peak,
+            curr_rate: stats.curr,
+        }
+    }
+}
+
+/// minio-go `replication.WorkerStat`. RustFS does not track per-bucket worker
+/// occupancy yet, so this always reports zeros.
+#[derive(Debug, Default, Clone, Copy, Serialize)]
+pub(crate) struct WorkerStatWire {
+    #[serde(rename = "curr")]
+    pub curr: i32,
+    #[serde(rename = "avg")]
+    pub avg: f32,
+    #[serde(rename = "max")]
+    pub max: i32,
+}
+
+/// minio-go `replication.ReplMRFStats`. RustFS does not track the 5-minute /
+/// dropped MRF windows, so this always reports zeros; the durable backlog is
+/// enumerable via `/v3/replication/mrf` instead.
+#[derive(Debug, Default, Clone, Copy, Serialize)]
+pub(crate) struct ReplMrfStatsWire {
+    #[serde(rename = "failedCount_last5min")]
+    pub last_failed_count: u64,
+    #[serde(rename = "droppedCount_since_uptime")]
+    pub total_dropped_count: u64,
+    #[serde(rename = "droppedBytes_since_uptime")]
+    pub total_dropped_bytes: u64,
+}
+
+/// minio-go `replication.CounterSummary`.
+#[derive(Debug, Default, Clone, Copy, Serialize)]
+pub(crate) struct CounterSummaryWire {
+    #[serde(rename = "last1hr")]
+    pub last1hr: u64,
+    #[serde(rename = "last1m")]
+    pub last1m: u64,
+    #[serde(rename = "total")]
+    pub total: u64,
+}
+
+/// minio-go `replication.TargetMetrics` (one remote target / ARN).
+#[derive(Debug, Default, Serialize)]
+pub(crate) struct TargetMetricsWire {
+    #[serde(rename = "replicationCount")]
+    pub replicated_count: i64,
+    #[serde(rename = "completedReplicationSize")]
+    pub replicated_size: i64,
+    /// Bandwidth limit for this target. The tag says "bits" but both MinIO
+    /// and minio-go treat the value as bytes/sec; keep bytes/sec.
+    #[serde(rename = "limitInBits")]
+    pub bandwidth_limit_bytes_per_sec: i64,
+    #[serde(rename = "currentBandwidth")]
+    pub current_bandwidth_bytes_per_sec: f64,
+    #[serde(rename = "failed")]
+    pub failed: TimedErrStatsWire,
+    #[serde(rename = "failedReplicationSize")]
+    pub failed_size: i64,
+    #[serde(rename = "failedReplicationCount")]
+    pub failed_count: i64,
+}
+
+fn target_timed_err_stats(stat: &InternalReplicationStat) -> TimedErrStatsWire {
+    // Cluster aggregation merges FailStats without the process-local samples,
+    // so the serializable window snapshots (refreshed at each node's
+    // collection point, summed by merge) are authoritative here; the live
+    // samples only ever agree with or lag them, so take the larger.
+    let sampled_minute = stat.fail_stats.recent_since(Duration::from_secs(60));
+    let sampled_hour = stat.fail_stats.recent_since(Duration::from_secs(3600));
+    let window = |sampled_count: i64, sampled_size: i64, snapshot_count: i64, snapshot_size: i64| RStatWire {
+        count: sampled_count.max(snapshot_count) as f64,
+        bytes: sampled_size.max(snapshot_size),
+    };
+    TimedErrStatsWire {
+        last_minute: window(
+            sampled_minute.count,
+            sampled_minute.size,
+            stat.fail_stats.last_minute.count,
+            stat.fail_stats.last_minute.size,
+        ),
+        last_hour: window(
+            sampled_hour.count,
+            sampled_hour.size,
+            stat.fail_stats.last_hour.count,
+            stat.fail_stats.last_hour.size,
+        ),
+        totals: RStatWire {
+            count: stat.failed.count as f64,
+            bytes: stat.failed.size,
+        },
+    }
+}
+
+impl From<&InternalReplicationStat> for TargetMetricsWire {
+    fn from(stat: &InternalReplicationStat) -> Self {
+        TargetMetricsWire {
+            replicated_count: stat.replicated_count,
+            replicated_size: stat.replicated_size,
+            bandwidth_limit_bytes_per_sec: stat.bandwidth_limit_bytes_per_sec,
+            current_bandwidth_bytes_per_sec: stat.current_bandwidth_bytes_per_sec,
+            failed: target_timed_err_stats(stat),
+            failed_size: stat.failed.size,
+            failed_count: stat.failed.count,
+        }
+    }
+}
+
+/// minio-go `replication.Metrics` — the `currStats` member of `MetricsV2` and
+/// the whole v1 response body. The trailing snake_case fields are RustFS
+/// source-health extension keys (ignored by Go decoders) carried over from
+/// the previous response shape.
+#[derive(Debug, Default, Serialize)]
+pub(crate) struct MetricsWire {
+    #[serde(rename = "Stats")]
+    pub stats: HashMap<String, TargetMetricsWire>,
+    #[serde(rename = "completedReplicationSize")]
+    pub replicated_size: i64,
+    #[serde(rename = "replicaSize")]
+    pub replica_size: i64,
+    #[serde(rename = "replicaCount")]
+    pub replica_count: i64,
+    #[serde(rename = "replicationCount")]
+    pub replicated_count: i64,
+    #[serde(rename = "failed")]
+    pub failed: TimedErrStatsWire,
+    #[serde(rename = "queued")]
+    pub queued: InQueueMetricWire,
+    // RustFS extension keys (source health of the aggregation).
+    pub provider_available: bool,
+    pub cluster_complete: bool,
+    pub observed_node_count: u32,
+    pub expected_node_count: u32,
+}
+
+impl From<&InternalReplicationStats> for MetricsWire {
+    fn from(stats: &InternalReplicationStats) -> Self {
+        let mut failed = TimedErrStatsWire::default();
+        let mut targets = HashMap::with_capacity(stats.stats.len());
+        for (arn, stat) in &stats.stats {
+            let target = TargetMetricsWire::from(stat);
+            failed = failed.add(target.failed);
+            targets.insert(arn.clone(), target);
+        }
+        MetricsWire {
+            stats: targets,
+            replicated_size: stats.replicated_size,
+            replica_size: stats.replica_size,
+            replica_count: stats.replica_count,
+            replicated_count: stats.replicated_count,
+            failed,
+            queued: InQueueMetricWire::from(&stats.q_stat),
+            provider_available: stats.provider_available,
+            cluster_complete: stats.cluster_complete,
+            observed_node_count: stats.observed_node_count,
+            expected_node_count: stats.expected_node_count,
+        }
+    }
+}
+
+/// minio-go `replication.ReplQNodeStats`.
+#[derive(Debug, Default, Serialize)]
+pub(crate) struct ReplQNodeStatsWire {
+    #[serde(rename = "nodeName")]
+    pub node_name: String,
+    #[serde(rename = "uptime")]
+    pub uptime: i64,
+    #[serde(rename = "activeWorkers")]
+    pub workers: WorkerStatWire,
+    #[serde(rename = "transferSummary")]
+    pub xfer_stats: XferSummaryWire,
+    #[serde(rename = "tgtTransferStats")]
+    pub tgt_xfer_stats: TargetXferSummaryWire,
+    #[serde(rename = "queueStats")]
+    pub q_stats: InQueueMetricWire,
+    #[serde(rename = "mrfStats")]
+    pub mrf_stats: ReplMrfStatsWire,
+    #[serde(rename = "retries")]
+    pub retries: CounterSummaryWire,
+    #[serde(rename = "errors")]
+    pub errors: CounterSummaryWire,
+}
+
+/// minio-go `replication.ReplQueueStats`.
+#[derive(Debug, Default, Serialize)]
+pub(crate) struct ReplQueueStatsWire {
+    #[serde(rename = "nodes")]
+    pub nodes: Vec<ReplQNodeStatsWire>,
+}
+
+/// minio-go `replication.MetricsV2` — the `?replication-metrics=2` body.
+#[derive(Debug, Default, Serialize)]
+pub(crate) struct MetricsV2Wire {
+    #[serde(rename = "uptime")]
+    pub uptime: i64,
+    #[serde(rename = "currStats")]
+    pub current_stats: MetricsWire,
+    #[serde(rename = "queueStats")]
+    pub queue_stats: ReplQueueStatsWire,
+    #[serde(rename = "downtimeInfo")]
+    pub downtime_info: HashMap<String, serde_json::Value>,
+}
+
+/// `transferSummary` map keyed by minio-go `MetricName` (Large/Small/Total).
+type XferSummaryWire = HashMap<&'static str, XferStatsWire>;
+/// `tgtTransferStats` map keyed by target ARN.
+type TargetXferSummaryWire = HashMap<String, XferSummaryWire>;
+
+fn transfer_summaries(stats: &InternalReplicationStats) -> (XferSummaryWire, TargetXferSummaryWire) {
+    let mut summary: XferSummaryWire = HashMap::new();
+    let mut per_target: TargetXferSummaryWire = HashMap::new();
+    for (arn, stat) in &stats.stats {
+        let large = XferStatsWire::from(&stat.xfer_rate_lrg);
+        let small = XferStatsWire::from(&stat.xfer_rate_sml);
+        let total = large.merge(small);
+        per_target.insert(arn.clone(), HashMap::from([("Large", large), ("Small", small), ("Total", total)]));
+        for (key, value) in [("Large", large), ("Small", small), ("Total", total)] {
+            let entry = summary.entry(key).or_default();
+            *entry = entry.merge(value);
+        }
+    }
+    (summary, per_target)
+}
+
+impl MetricsV2Wire {
+    /// Project the aggregated internal stats onto the `MetricsV2` shape.
+    ///
+    /// The aggregation path leaves `queue_stats.nodes` empty today, so a
+    /// single node entry is synthesized from the bucket queue snapshot —
+    /// `mc replicate status` derives its queue/worker panels from
+    /// `queueStats.nodes` and treats an empty list as "no data".
+    pub(crate) fn from_stats(bucket_stats: &BucketStats, node_name: &str) -> Self {
+        let (xfer_stats, tgt_xfer_stats) = transfer_summaries(&bucket_stats.replication_stats);
+        let mut nodes: Vec<ReplQNodeStatsWire> = bucket_stats
+            .queue_stats
+            .nodes
+            .iter()
+            .map(|node| ReplQNodeStatsWire {
+                node_name: node_name.to_string(),
+                uptime: bucket_stats.uptime,
+                q_stats: InQueueMetricWire::from(&node.q_stats),
+                ..Default::default()
+            })
+            .collect();
+        if nodes.is_empty() {
+            nodes.push(ReplQNodeStatsWire {
+                node_name: node_name.to_string(),
+                uptime: bucket_stats.uptime,
+                q_stats: InQueueMetricWire::from(&bucket_stats.replication_stats.q_stat),
+                xfer_stats: xfer_stats.clone(),
+                tgt_xfer_stats: tgt_xfer_stats.clone(),
+                ..Default::default()
+            });
+        } else {
+            // Attach the transfer summaries to the first node; the internal
+            // snapshot does not attribute transfer rates per node.
+            if let Some(first) = nodes.first_mut() {
+                first.xfer_stats = xfer_stats.clone();
+                first.tgt_xfer_stats = tgt_xfer_stats.clone();
+            }
+        }
+
+        MetricsV2Wire {
+            uptime: bucket_stats.uptime,
+            current_stats: MetricsWire::from(&bucket_stats.replication_stats),
+            queue_stats: ReplQueueStatsWire { nodes },
+            downtime_info: HashMap::new(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn sample_bucket_stats() -> BucketStats {
+        let mut stats = BucketStats {
+            uptime: 42,
+            ..Default::default()
+        };
+        stats.replication_stats.replica_count = 2;
+        stats.replication_stats.replica_size = 128;
+        stats.replication_stats.replicated_count = 9;
+        stats.replication_stats.replicated_size = 4096;
+        let target = stats
+            .replication_stats
+            .stats
+            .entry("arn:minio:replication::t:b".to_string())
+            .or_default();
+        target.replicated_count = 9;
+        target.replicated_size = 4096;
+        target.failed.count = 3;
+        target.failed.size = 900;
+        target.bandwidth_limit_bytes_per_sec = 1024;
+        target.current_bandwidth_bytes_per_sec = 512.5;
+        stats
+            .replication_stats
+            .q_stat
+            .curr
+            .now_count
+            .store(4, std::sync::atomic::Ordering::Relaxed);
+        stats
+            .replication_stats
+            .q_stat
+            .curr
+            .now_bytes
+            .store(1200, std::sync::atomic::Ordering::Relaxed);
+        stats.replication_stats.q_stat = stats.replication_stats.q_stat.snapshot();
+        stats
+    }
+
+    #[test]
+    fn metrics_wire_matches_minio_go_tags() {
+        let stats = sample_bucket_stats();
+        let json = serde_json::to_value(MetricsWire::from(&stats.replication_stats)).expect("v1 wire should serialize");
+
+        assert_eq!(json["replicaCount"], 2);
+        assert_eq!(json["replicaSize"], 128);
+        assert_eq!(json["replicationCount"], 9);
+        assert_eq!(json["completedReplicationSize"], 4096);
+        assert_eq!(json["queued"]["curr"]["count"], 4.0);
+        assert_eq!(json["queued"]["curr"]["bytes"], 1200.0);
+        let target = &json["Stats"]["arn:minio:replication::t:b"];
+        assert_eq!(target["replicationCount"], 9);
+        assert_eq!(target["completedReplicationSize"], 4096);
+        assert_eq!(target["limitInBits"], 1024);
+        assert_eq!(target["currentBandwidth"], 512.5);
+        // failed is the madmin TimedErrStats envelope, not the internal
+        // {count,size} pair.
+        assert_eq!(target["failed"]["totals"]["count"], 3.0);
+        assert_eq!(target["failed"]["totals"]["bytes"], 900);
+        assert!(target["failed"].get("count").is_none());
+        // Aggregate failed mirrors the per-target totals.
+        assert_eq!(json["failed"]["totals"]["count"], 3.0);
+    }
+
+    #[test]
+    fn metrics_v2_wire_synthesizes_queue_node() {
+        let stats = sample_bucket_stats();
+        let json = serde_json::to_value(MetricsV2Wire::from_stats(&stats, "node-1:9000")).expect("v2 wire should serialize");
+
+        assert_eq!(json["uptime"], 42);
+        assert_eq!(json["currStats"]["replicaCount"], 2);
+        let node = &json["queueStats"]["nodes"][0];
+        assert_eq!(node["nodeName"], "node-1:9000");
+        assert_eq!(node["uptime"], 42);
+        assert_eq!(node["queueStats"]["curr"]["count"], 4.0);
+        // The queue peak is emitted under both the minio-go tag (`peak`) and
+        // the MinIO server tag (`max`).
+        assert_eq!(node["queueStats"]["peak"], node["queueStats"]["max"]);
+        assert!(node["activeWorkers"].get("curr").is_some());
+        assert!(node["transferSummary"].get("Total").is_some());
+        assert_eq!(json["downtimeInfo"], serde_json::json!({}));
+    }
+
+    /// minio-go's transferSummary labels mean >= 128 MiB for Large; the
+    /// producer must bin on the same boundary (MIN_LARGE_OBJ_SIZE, shared
+    /// with the worker-pool split), or a 2 MiB replication shows under Large
+    /// while Small stays zero.
+    #[test]
+    fn transfer_summary_bins_on_the_128_mib_boundary() {
+        const MIB: i64 = 1024 * 1024;
+        let mut stats = BucketStats::default();
+        let stat = stats
+            .replication_stats
+            .stats
+            .entry("arn:minio:replication::t:b".to_string())
+            .or_default();
+        stat.update_xfer_rate(2 * MIB, std::time::Duration::from_secs(1));
+        stat.update_xfer_rate(127 * MIB, std::time::Duration::from_secs(1));
+        stat.update_xfer_rate(128 * MIB, std::time::Duration::from_secs(1));
+
+        let json = serde_json::to_value(MetricsV2Wire::from_stats(&stats, "node-1")).expect("v2 wire should serialize");
+        let summary = &json["queueStats"]["nodes"][0]["tgtTransferStats"]["arn:minio:replication::t:b"];
+        let small_peak = summary["Small"]["peakRate"].as_f64().expect("Small peakRate");
+        let large_peak = summary["Large"]["peakRate"].as_f64().expect("Large peakRate");
+        assert!(
+            (small_peak - (127 * MIB) as f64).abs() < 1.0,
+            "2 MiB and 127 MiB transfers must bin as Small (peak {small_peak})"
+        );
+        assert!(
+            (large_peak - (128 * MIB) as f64).abs() < 1.0,
+            "exactly 128 MiB must bin as Large (peak {large_peak})"
+        );
+    }
+
+    /// Review regression: both metrics endpoints aggregate first, and the
+    /// FailStats merge drops the process-local samples — the rolling windows
+    /// must survive a peer-RPC round trip plus aggregation and still reach
+    /// the wire body.
+    #[test]
+    fn failure_windows_survive_aggregation_before_serialization() {
+        // Node A: live failure; the windows are stamped at the collection
+        // point (get_latest_replication_stats calls refresh_windows before
+        // the stats cross the wire), never on the failure hot path.
+        let mut node_a = crate::admin::storage_api::replication::BucketReplicationStat::default();
+        node_a.fail_stats.add_size(512, None::<&std::io::Error>);
+        node_a.fail_stats.refresh_windows();
+        node_a.failed = node_a.fail_stats.to_metric();
+
+        // Node A's stats cross the peer RPC wire: the samples are dropped,
+        // the window snapshots travel.
+        let encoded = rmp_serde::to_vec_named(&node_a).expect("stat should encode");
+        let remote: crate::admin::storage_api::replication::BucketReplicationStat =
+            rmp_serde::from_slice(&encoded).expect("stat should decode");
+
+        // Aggregation merges the remote stat with an empty local one.
+        let merged_fail = remote.fail_stats.merge(&Default::default());
+        let mut aggregated = crate::admin::storage_api::replication::BucketReplicationStat::default();
+        aggregated.failed = merged_fail.to_metric();
+        aggregated.fail_stats = merged_fail;
+
+        let mut stats = BucketStats::default();
+        stats
+            .replication_stats
+            .stats
+            .insert("arn:minio:replication::t:b".to_string(), aggregated);
+
+        let json = serde_json::to_value(MetricsWire::from(&stats.replication_stats)).expect("wire should serialize");
+        let failed = &json["Stats"]["arn:minio:replication::t:b"]["failed"];
+        assert_eq!(failed["totals"]["count"], 1.0);
+        assert_eq!(
+            failed["lastMinute"]["count"], 1.0,
+            "the rolling minute window must survive RPC + aggregation"
+        );
+        assert_eq!(failed["lastMinute"]["bytes"], 512);
+        assert_eq!(failed["lastHour"]["count"], 1.0);
+    }
+
+    /// Pin the intra-cluster peer-RPC wire format of the internal stats: it
+    /// is msgpack with the Rust field names as map keys
+    /// (`rmp_serde::to_vec_named` in node_service.rs). If someone "fixes"
+    /// the interop bug by renaming the internal serde fields instead of using
+    /// these DTOs, this test fails and points them here.
+    #[test]
+    fn internal_bucket_stats_rpc_wire_stays_snake_case() {
+        let stats = sample_bucket_stats();
+        let encoded = rmp_serde::to_vec_named(&stats).expect("internal stats should encode");
+        let value: serde_json::Value = rmp_serde::from_slice(&encoded).expect("named msgpack should decode generically");
+
+        assert!(
+            value.get("replication_stats").is_some(),
+            "peer RPC key replication_stats must not be renamed"
+        );
+        assert!(value["replication_stats"].get("q_stat").is_some());
+        assert!(value.get("queue_stats").is_some());
+        assert!(value.get("proxy_stats").is_some());
+
+        let decoded: BucketStats = rmp_serde::from_slice(&encoded).expect("round-trip through the peer RPC wire");
+        assert_eq!(decoded.replication_stats.replica_count, 2);
+    }
+}

rustfs/src/admin/router.rs

@@ -1548,7 +1548,8 @@ async fn build_replication_metrics_response(
     let bucket_stats = apply_replication_metrics_bandwidth_report(bucket_stats, collect_replication_metrics_bandwidth(bucket));
     let bucket_stats = apply_replication_metrics_runtime_fields(bucket_stats, route, replication_metrics_uptime_seconds());
 
-    let body = serialize_replication_metrics_body(&bucket_stats, route)?;
+    let node_name = crate::runtime_sources::current_local_node_name().await.unwrap_or_default();
+    let body = serialize_replication_metrics_body(&bucket_stats, route, &node_name)?;
 
     let mut resp = S3Response::with_status(Body::from(body), StatusCode::OK);
     resp.headers
@@ -1608,12 +1609,24 @@ fn apply_replication_metrics_runtime_fields(
     bucket_stats
 }
 
-fn serialize_replication_metrics_body(bucket_stats: &BucketStats, route: ReplicationExtRoute) -> S3Result<Vec<u8>> {
+/// Serialize the metrics body in the minio-go wire shapes
+/// (`replication.Metrics` for v1, `replication.MetricsV2` for v2). The
+/// internal `BucketStats` serde names are the intra-cluster peer-RPC wire
+/// format and must never appear here — see
+/// `crate::admin::replication_metrics_wire`.
+fn serialize_replication_metrics_body(
+    bucket_stats: &BucketStats,
+    route: ReplicationExtRoute,
+    node_name: &str,
+) -> S3Result<Vec<u8>> {
+    use crate::admin::replication_metrics_wire::{MetricsV2Wire, MetricsWire};
     match route {
         ReplicationExtRoute::MetricsV1 => {
-            serde_json::to_vec(&bucket_stats.replication_stats).map_err(|e| s3_error!(InternalError, "{e}"))
+            serde_json::to_vec(&MetricsWire::from(&bucket_stats.replication_stats)).map_err(|e| s3_error!(InternalError, "{e}"))
+        }
+        ReplicationExtRoute::MetricsV2 => {
+            serde_json::to_vec(&MetricsV2Wire::from_stats(bucket_stats, node_name)).map_err(|e| s3_error!(InternalError, "{e}"))
         }
-        ReplicationExtRoute::MetricsV2 => serde_json::to_vec(bucket_stats).map_err(|e| s3_error!(InternalError, "{e}")),
         ReplicationExtRoute::Check | ReplicationExtRoute::ResetStart | ReplicationExtRoute::ResetStatus => {
             Err(s3_error!(InternalError, "invalid route for metrics response"))
         }
@@ -4147,22 +4160,37 @@ mod tests {
         assert!(err.message().unwrap_or_default().contains("rule-stale"));
     }
 
+    /// The v1 body must decode into minio-go `replication.Metrics` (exact
+    /// json tags); Go's decoder matches case-insensitively but does not
+    /// ignore underscores, so the internal snake_case names read as all-zero.
     #[test]
-    fn serialize_replication_metrics_body_v1_returns_replication_stats_only() {
+    fn serialize_replication_metrics_body_v1_returns_minio_go_metrics_shape() {
         let mut stats = BucketStats {
             uptime: 99,
             ..Default::default()
         };
         stats.replication_stats.replica_count = 7;
+        stats.replication_stats.replicated_size = 2048;
+        stats
+            .replication_stats
+            .stats
+            .entry("arn:minio:replication::t:b".to_string())
+            .or_default()
+            .replicated_count = 5;
         stats.proxy_stats.put_total = 3;
 
-        let body =
-            serialize_replication_metrics_body(&stats, ReplicationExtRoute::MetricsV1).expect("metrics v1 body should serialize");
+        let body = serialize_replication_metrics_body(&stats, ReplicationExtRoute::MetricsV1, "node-1:9000")
+            .expect("metrics v1 body should serialize");
         let payload: serde_json::Value = serde_json::from_slice(&body).expect("body should be json");
 
-        assert_eq!(payload["replica_count"], 7);
+        assert_eq!(payload["replicaCount"], 7);
+        assert_eq!(payload["completedReplicationSize"], 2048);
+        assert_eq!(payload["Stats"]["arn:minio:replication::t:b"]["replicationCount"], 5);
         assert!(payload.get("uptime").is_none());
         assert!(payload.get("proxy_stats").is_none());
+        // The internal snake_case names must not leak into the wire body.
+        assert!(payload.get("replica_count").is_none());
+        assert!(payload.get("q_stat").is_none());
     }
 
     #[test]
@@ -4248,22 +4276,48 @@ mod tests {
         assert_eq!(target.current_bandwidth_bytes_per_sec, 3000.0);
     }
 
+    /// The v2 body must decode into minio-go `replication.MetricsV2`
+    /// (`uptime`/`currStats`/`queueStats`); `mc replicate status` reads
+    /// `currStats` and `queueStats.nodes` and silently shows zeros when the
+    /// keys do not match.
     #[test]
-    fn serialize_replication_metrics_body_v2_returns_full_bucket_stats() {
+    fn serialize_replication_metrics_body_v2_returns_minio_go_metrics_v2_shape() {
         let mut stats = BucketStats {
             uptime: 99,
             ..Default::default()
         };
         stats.replication_stats.replica_count = 7;
+        stats
+            .replication_stats
+            .q_stat
+            .curr
+            .now_count
+            .store(4, std::sync::atomic::Ordering::Relaxed);
+        stats
+            .replication_stats
+            .q_stat
+            .curr
+            .now_bytes
+            .store(1200, std::sync::atomic::Ordering::Relaxed);
+        stats.replication_stats.q_stat = stats.replication_stats.q_stat.snapshot();
         stats.proxy_stats.put_total = 3;
 
-        let body =
-            serialize_replication_metrics_body(&stats, ReplicationExtRoute::MetricsV2).expect("metrics v2 body should serialize");
+        let body = serialize_replication_metrics_body(&stats, ReplicationExtRoute::MetricsV2, "node-1:9000")
+            .expect("metrics v2 body should serialize");
         let payload: serde_json::Value = serde_json::from_slice(&body).expect("body should be json");
 
         assert_eq!(payload["uptime"], 99);
-        assert_eq!(payload["replication_stats"]["replica_count"], 7);
-        assert_eq!(payload["proxy_stats"]["put_total"], 3);
+        assert_eq!(payload["currStats"]["replicaCount"], 7);
+        assert_eq!(payload["currStats"]["queued"]["curr"]["count"], 4.0);
+        // The queue snapshot must surface at least one node: mc derives the
+        // worker/queue panels from queueStats.nodes and treats an empty list
+        // as "no data".
+        assert_eq!(payload["queueStats"]["nodes"][0]["queueStats"]["curr"]["count"], 4.0);
+        assert_eq!(payload["queueStats"]["nodes"][0]["uptime"], 99);
+        // The internal snake_case names must not leak into the wire body.
+        assert!(payload.get("replication_stats").is_none());
+        assert!(payload.get("queue_stats").is_none());
+        assert!(payload.get("proxy_stats").is_none());
     }
 
     #[test]

rustfs/src/admin/storage_api.rs

@@ -417,6 +417,10 @@ pub(crate) mod replication {
     };
     pub(crate) type BucketReplicationResyncStatus = super::ecstore_bucket::replication::BucketReplicationResyncStatus;
     pub(crate) type BucketStats = super::ecstore_bucket::replication::BucketStats;
+    pub(crate) type BucketReplicationStats = super::ecstore_bucket::replication::BucketReplicationStats;
+    pub(crate) type BucketReplicationStat = super::ecstore_bucket::replication::BucketReplicationStat;
+    pub(crate) type InQueueMetric = super::ecstore_bucket::replication::InQueueMetric;
+    pub(crate) type XferStats = super::ecstore_bucket::replication::XferStats;
     pub(crate) type ReplicationStatusType = super::ecstore_bucket::replication::ReplicationStatusType;
     pub(crate) type ResyncOpts = super::ecstore_bucket::replication::ResyncOpts;
     pub(crate) type ResyncStatusType = super::ecstore_bucket::replication::ResyncStatusType;