test(scanner): isolate nil identity regressions

Test-only combination of observed source 839467a0 with queue changes c96fc5cf and scoped tests 41d06b4d.

Cargo.lock

@@ -9858,6 +9858,7 @@ version = "1.0.2"
 dependencies = [
  "serde",
  "serde_json",
+ "thiserror 2.0.21",
  "tokio",
  "uuid",
 ]

crates/heal-contracts/Cargo.toml

@@ -29,8 +29,9 @@ workspace = true
 
 [dependencies]
 serde = { workspace = true, features = ["derive"] }
+thiserror.workspace = true
 tokio = { workspace = true, features = ["sync"] }
-uuid = { workspace = true, features = ["v4", "fast-rng", "macro-diagnostics"] }
+uuid = { workspace = true, features = ["v4", "serde", "fast-rng", "macro-diagnostics"] }
 
 [dev-dependencies]
 serde_json = { workspace = true }

crates/heal-contracts/src/completion.rs

@@ -18,12 +18,25 @@ use crate::{
     heal_channel::HealScanMode,
     outcome::{HealExecutionOutcome, HealObjectReceipt},
 };
-use std::sync::{Arc, OnceLock};
+use std::sync::{
+    Arc, OnceLock,
+    atomic::{AtomicU64, Ordering},
+};
 use tokio::sync::broadcast;
 
 pub const MAX_COMPLETION_IDENTITY_BYTES: usize = 4096;
 const COMPLETION_CHANNEL_CAPACITY: usize = 1024;
 
+/// A process-local observation identity. It is never persisted or sent over RPC.
+pub type HealObservationId = u64;
+
+/// Allocate one identity per accepted owner. Exhaustion is reported as unknown.
+pub fn new_heal_observation_id() -> Option<HealObservationId> {
+    static NEXT: AtomicU64 = AtomicU64::new(1);
+    NEXT.try_update(Ordering::Relaxed, Ordering::Relaxed, |value| value.checked_add(1))
+        .ok()
+}
+
 #[derive(Debug, Clone)]
 pub struct HealCompletion {
     /// The accepted owner, never a discarded merged request ID.
@@ -36,33 +49,84 @@ pub struct HealCompletion {
     pub object: Option<HealObjectReceipt>,
 }
 
-fn sender() -> &'static broadcast::Sender<Arc<HealCompletion>> {
-    static SENDER: OnceLock<broadcast::Sender<Arc<HealCompletion>>> = OnceLock::new();
-    SENDER.get_or_init(|| broadcast::channel(COMPLETION_CHANNEL_CAPACITY).0)
+/// A completion paired with an optional in-process owner identity.
+#[derive(Debug, Clone)]
+pub struct ObservedHealCompletion {
+    pub completion: Arc<HealCompletion>,
+    pub observation_id: Option<HealObservationId>,
+}
+
+impl std::ops::Deref for ObservedHealCompletion {
+    type Target = HealCompletion;
+
+    fn deref(&self) -> &Self::Target {
+        &self.completion
+    }
+}
+
+struct CompletionBroadcaster {
+    legacy: broadcast::Sender<Arc<HealCompletion>>,
+    observed: broadcast::Sender<Arc<ObservedHealCompletion>>,
+}
+
+impl CompletionBroadcaster {
+    fn new(capacity: usize) -> Self {
+        Self {
+            legacy: broadcast::channel(capacity).0,
+            observed: broadcast::channel(capacity).0,
+        }
+    }
+
+    fn has_observers(&self) -> bool {
+        self.legacy.receiver_count() > 0 || self.observed.receiver_count() > 0
+    }
+
+    fn publish(&self, completion: HealCompletion, observation_id: Option<HealObservationId>) {
+        let identity_bytes = completion.object.as_ref().map_or(0, |object| {
+            object
+                .identity
+                .bucket
+                .capacity()
+                .saturating_add(object.identity.object.capacity())
+                .saturating_add(object.identity.version_id.as_ref().map_or(0, String::capacity))
+        });
+        if completion.task_id.capacity().saturating_add(identity_bytes) <= MAX_COMPLETION_IDENTITY_BYTES {
+            let completion = Arc::new(completion);
+            let _ = self.legacy.send(Arc::clone(&completion));
+            let _ = self.observed.send(Arc::new(ObservedHealCompletion {
+                completion,
+                observation_id,
+            }));
+        }
+    }
+}
+
+fn broadcaster() -> &'static CompletionBroadcaster {
+    static BROADCASTER: OnceLock<CompletionBroadcaster> = OnceLock::new();
+    BROADCASTER.get_or_init(|| CompletionBroadcaster::new(COMPLETION_CHANNEL_CAPACITY))
 }
 
 pub fn has_heal_completion_observers() -> bool {
-    sender().receiver_count() > 0
+    broadcaster().has_observers()
 }
 
 /// Subscribe before admission so a fast worker cannot precede subscription.
 pub fn subscribe_heal_completions() -> broadcast::Receiver<Arc<HealCompletion>> {
-    sender().subscribe()
+    broadcaster().legacy.subscribe()
+}
+
+pub fn subscribe_observed_heal_completions() -> broadcast::Receiver<Arc<ObservedHealCompletion>> {
+    broadcaster().observed.subscribe()
 }
 
 /// Oversized diagnostics and lagging consumers lose observations, never repairs.
 pub fn publish_heal_completion(completion: HealCompletion) {
-    let identity_bytes = completion.object.as_ref().map_or(0, |object| {
-        object
-            .identity
-            .bucket
-            .capacity()
-            .saturating_add(object.identity.object.capacity())
-            .saturating_add(object.identity.version_id.as_ref().map_or(0, String::capacity))
-    });
-    if completion.task_id.capacity().saturating_add(identity_bytes) <= MAX_COMPLETION_IDENTITY_BYTES {
-        let _ = sender().send(Arc::new(completion));
-    }
+    publish_observed_heal_completion(completion, None);
+}
+
+/// Each channel is FIFO independently; relative delivery across channels is not ordered.
+pub fn publish_observed_heal_completion(completion: HealCompletion, observation_id: Option<HealObservationId>) {
+    broadcaster().publish(completion, observation_id);
 }
 
 #[cfg(test)]
@@ -70,36 +134,155 @@ mod tests {
     use super::*;
 
     #[test]
-    fn completion_delivery_is_bounded_and_does_not_require_a_consumer() {
-        let mut receiver = subscribe_heal_completions();
+    fn public_completion_facades_share_receipts_and_preserve_missing_tokens() {
+        // Other completion tests use private broadcasters, keeping this global
+        // facade test isolated from their capacity and lag checks.
+        let mut legacy = subscribe_heal_completions();
+        let mut observed = subscribe_observed_heal_completions();
+        let completion = HealCompletion {
+            task_id: uuid::Uuid::new_v4().to_string(),
+            scan_mode: HealScanMode::Deep,
+            dry_run: false,
+            execution: None,
+            object: None,
+        };
+        publish_heal_completion(completion.clone());
+        let legacy_event = legacy.try_recv().expect("legacy subscriber receives old API event");
+        let observed_event = observed.try_recv().expect("observer receives old API event");
+        assert!(Arc::ptr_eq(&legacy_event, &observed_event.completion));
+        assert_eq!(legacy_event.task_id, completion.task_id);
+        assert_eq!(observed_event.observation_id, None);
+
+        publish_observed_heal_completion(completion, Some(51));
+        let legacy_event = legacy.try_recv().expect("legacy subscriber receives observed API event");
+        let observed_event = observed.try_recv().expect("observer receives observed API event");
+        assert!(Arc::ptr_eq(&legacy_event, &observed_event.completion));
+        assert_eq!(observed_event.observation_id, Some(51));
+    }
+
+    #[test]
+    fn legacy_and_observed_subscribers_receive_the_same_completion_in_each_channel_order() {
+        let id = uuid::Uuid::new_v4().to_string();
+        let bus = CompletionBroadcaster::new(COMPLETION_CHANNEL_CAPACITY);
+        let mut legacy = bus.legacy.subscribe();
+        let mut observed = bus.observed.subscribe();
+        assert!(bus.has_observers());
+        for (suffix, token) in [("first", Some(41)), ("second", None)] {
+            bus.publish(
+                HealCompletion {
+                    task_id: format!("{id}-{suffix}"),
+                    scan_mode: HealScanMode::Normal,
+                    dry_run: false,
+                    execution: None,
+                    object: None,
+                },
+                token,
+            );
+        }
+        for (suffix, token) in [("first", Some(41)), ("second", None)] {
+            let expected = format!("{id}-{suffix}");
+            let legacy_event = loop {
+                let event = legacy.try_recv().expect("legacy completion");
+                if event.task_id == expected {
+                    break event;
+                }
+            };
+            let observed_event = loop {
+                let event = observed.try_recv().expect("observed completion");
+                if event.task_id == expected {
+                    break event;
+                }
+            };
+            assert!(Arc::ptr_eq(&legacy_event, &observed_event.completion));
+            assert_eq!(observed_event.observation_id, token);
+        }
+        drop(legacy);
+        assert!(bus.has_observers(), "observed-only subscribers require completion construction");
+        let completion = HealCompletion {
+            task_id: id.clone(),
+            scan_mode: HealScanMode::Deep,
+            dry_run: false,
+            execution: None,
+            object: None,
+        };
+        bus.publish(completion, None);
+        let observed_event = loop {
+            let event = observed.try_recv().expect("legacy publication reaches observed channel");
+            if event.task_id == id {
+                break event;
+            }
+        };
+        assert_eq!(observed_event.observation_id, None);
+    }
+
+    #[test]
+    fn legacy_and_observed_channels_report_lag_independently() {
+        let bus = CompletionBroadcaster::new(COMPLETION_CHANNEL_CAPACITY);
+        let mut legacy = bus.legacy.subscribe();
+        let mut observed = bus.observed.subscribe();
         for index in 0..=COMPLETION_CHANNEL_CAPACITY {
-            publish_heal_completion(HealCompletion {
-                task_id: format!("task-{index}"),
-                scan_mode: HealScanMode::Deep,
-                dry_run: false,
-                execution: Some(HealExecutionOutcome::Completed),
-                object: None,
-            });
+            bus.publish(
+                HealCompletion {
+                    task_id: format!("dual-lag-{index}"),
+                    scan_mode: HealScanMode::Normal,
+                    dry_run: false,
+                    execution: None,
+                    object: None,
+                },
+                Some(42),
+            );
+        }
+        assert!(matches!(legacy.try_recv(), Err(broadcast::error::TryRecvError::Lagged(_))));
+        assert!(matches!(observed.try_recv(), Err(broadcast::error::TryRecvError::Lagged(_))));
+    }
+
+    #[test]
+    fn completion_delivery_is_bounded_and_does_not_require_a_consumer() {
+        let bus = CompletionBroadcaster::new(COMPLETION_CHANNEL_CAPACITY);
+        assert!(!bus.has_observers());
+        let mut receiver = bus.legacy.subscribe();
+        assert!(bus.has_observers());
+        for index in 0..=COMPLETION_CHANNEL_CAPACITY {
+            bus.publish(
+                HealCompletion {
+                    task_id: format!("task-{index}"),
+                    scan_mode: HealScanMode::Deep,
+                    dry_run: false,
+                    execution: Some(HealExecutionOutcome::Completed),
+                    object: None,
+                },
+                None,
+            );
         }
         assert!(matches!(receiver.try_recv(), Err(broadcast::error::TryRecvError::Lagged(1))));
         while receiver.try_recv().is_ok() {}
         let mut oversized = String::with_capacity(MAX_COMPLETION_IDENTITY_BYTES + 1);
         oversized.push_str("short-but-large-allocation");
-        publish_heal_completion(HealCompletion {
-            task_id: oversized,
-            scan_mode: HealScanMode::Deep,
-            dry_run: false,
-            execution: None,
-            object: None,
-        });
+        let mut observed = bus.observed.subscribe();
+        bus.publish(
+            HealCompletion {
+                task_id: oversized,
+                scan_mode: HealScanMode::Deep,
+                dry_run: false,
+                execution: None,
+                object: None,
+            },
+            None,
+        );
         assert!(matches!(receiver.try_recv(), Err(broadcast::error::TryRecvError::Empty)));
+        assert!(matches!(observed.try_recv(), Err(broadcast::error::TryRecvError::Empty)));
         drop(receiver);
-        publish_heal_completion(HealCompletion {
-            task_id: "no-consumer".into(),
-            scan_mode: HealScanMode::Deep,
-            dry_run: false,
-            execution: Some(HealExecutionOutcome::Completed),
-            object: None,
-        });
+        drop(observed);
+        assert!(!bus.has_observers());
+        bus.publish(
+            HealCompletion {
+                task_id: "no-consumer".into(),
+                scan_mode: HealScanMode::Deep,
+                dry_run: false,
+                execution: Some(HealExecutionOutcome::Completed),
+                object: None,
+            },
+            None,
+        );
     }
 }

crates/heal-contracts/src/heal_channel.rs

@@ -271,6 +271,39 @@ pub struct HealAdmissionReceipt {
     pub task_id: String,
 }
 
+/// Optional process-local observation metadata for a canonical receipt.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ObservedHealAdmissionReceipt {
+    pub receipt: HealAdmissionReceipt,
+    /// Process-local owner identity; absent for remote or unproven owners.
+    pub observation_id: Option<crate::completion::HealObservationId>,
+}
+
+/// Errors from process-local observed admission and its channel initialization.
+#[derive(Debug, thiserror::Error)]
+pub enum HealObservationChannelError {
+    #[error("Heal channel sender already initialized")]
+    AlreadyInitialized,
+    #[error("Heal channel not initialized")]
+    NotInitialized,
+    #[error("Heal receipt command channel closed")]
+    LegacyCommandClosed,
+    #[error("Failed to receive heal admission response: {0}")]
+    LegacyResponseClosed(#[source] oneshot::error::RecvError),
+    #[error("Failed to receive observed heal admission response: {0}")]
+    ObservedResponseClosed(#[source] oneshot::error::RecvError),
+    #[error("{0}")]
+    AdmissionFailed(String),
+}
+
+impl std::ops::Deref for ObservedHealAdmissionReceipt {
+    type Target = HealAdmissionReceipt;
+
+    fn deref(&self) -> &Self::Target {
+        &self.receipt
+    }
+}
+
 impl HealAdmissionResult {
     pub fn result_label(self) -> &'static str {
         match self {
@@ -447,9 +480,19 @@ pub struct HealReceiptCommand {
 /// Canonical-receipt command receiver.
 pub type HealReceiptReceiver = mpsc::UnboundedReceiver<HealReceiptCommand>;
 
+/// Process-local admission command carrying an observed receipt.
+#[derive(Debug)]
+pub struct ObservedHealReceiptCommand {
+    pub request: HealChannelRequest,
+    pub response_tx: oneshot::Sender<Result<ObservedHealAdmissionReceipt, HealObservationChannelError>>,
+}
+
+pub type ObservedHealReceiptReceiver = mpsc::UnboundedReceiver<ObservedHealReceiptCommand>;
+
 struct HealChannelSenders {
     command: HealChannelSender,
     receipt: mpsc::UnboundedSender<HealReceiptCommand>,
+    observed: Option<mpsc::UnboundedSender<ObservedHealReceiptCommand>>,
 }
 
 /// Global heal channel sender
@@ -469,12 +512,31 @@ pub fn init_heal_channel() -> Result<HealChannelReceiver, &'static str> {
 
 /// Initialize the legacy command and canonical-receipt channels atomically.
 pub fn init_heal_channels() -> Result<(HealChannelReceiver, HealReceiptReceiver), &'static str> {
+    let (command_receiver, receipt_receiver, _) =
+        init_heal_channels_inner(false).map_err(|_| "Heal channel sender already initialized")?;
+    Ok((command_receiver, receipt_receiver))
+}
+
+/// Initialize an additional local observation channel while preserving the legacy channels.
+pub fn init_heal_channels_with_observations()
+-> Result<(HealChannelReceiver, HealReceiptReceiver, ObservedHealReceiptReceiver), HealObservationChannelError> {
+    init_heal_channels_inner(true)
+}
+
+fn init_heal_channels_inner(
+    with_observations: bool,
+) -> Result<(HealChannelReceiver, HealReceiptReceiver, ObservedHealReceiptReceiver), HealObservationChannelError> {
     let (command, command_receiver) = mpsc::unbounded_channel();
     let (receipt, receipt_receiver) = mpsc::unbounded_channel();
+    let (observed, observed_receiver) = mpsc::unbounded_channel();
     GLOBAL_HEAL_CHANNEL_SENDERS
-        .set(HealChannelSenders { command, receipt })
-        .map_err(|_| "Heal channel sender already initialized")?;
-    Ok((command_receiver, receipt_receiver))
+        .set(HealChannelSenders {
+            command,
+            receipt,
+            observed: with_observations.then_some(observed),
+        })
+        .map_err(|_| HealObservationChannelError::AlreadyInitialized)?;
+    Ok((command_receiver, receipt_receiver, observed_receiver))
 }
 
 /// Get global heal channel sender
@@ -515,10 +577,17 @@ pub fn subscribe_heal_responses() -> broadcast::Receiver<HealChannelResponse> {
 
 /// Send heal start request and wait for structured admission feedback.
 pub async fn send_heal_request_with_receipt(request: HealChannelRequest) -> Result<HealAdmissionReceipt, String> {
-    let (response_tx, response_rx) = oneshot::channel();
     let senders = GLOBAL_HEAL_CHANNEL_SENDERS
         .get()
         .ok_or_else(|| "Heal channel not initialized".to_string())?;
+    send_heal_request_with_receipt_on(senders, request).await
+}
+
+async fn send_heal_request_with_receipt_on(
+    senders: &HealChannelSenders,
+    request: HealChannelRequest,
+) -> Result<HealAdmissionReceipt, String> {
+    let (response_tx, response_rx) = oneshot::channel();
     senders
         .receipt
         .send(HealReceiptCommand { request, response_tx })
@@ -528,6 +597,46 @@ pub async fn send_heal_request_with_receipt(request: HealChannelRequest) -> Resu
         .map_err(|e| format!("Failed to receive heal admission response: {e}"))?
 }
 
+/// A missing or closed observation channel falls back only before a command is accepted.
+pub async fn send_heal_request_with_observation(
+    request: HealChannelRequest,
+) -> Result<ObservedHealAdmissionReceipt, HealObservationChannelError> {
+    let senders = GLOBAL_HEAL_CHANNEL_SENDERS
+        .get()
+        .ok_or(HealObservationChannelError::NotInitialized)?;
+    send_heal_request_with_observation_on(senders, request).await
+}
+
+async fn send_heal_request_with_observation_on(
+    senders: &HealChannelSenders,
+    mut request: HealChannelRequest,
+) -> Result<ObservedHealAdmissionReceipt, HealObservationChannelError> {
+    if let Some(observed) = &senders.observed {
+        let (response_tx, response_rx) = oneshot::channel();
+        match observed.send(ObservedHealReceiptCommand { request, response_tx }) {
+            Ok(()) => {
+                return response_rx
+                    .await
+                    .map_err(HealObservationChannelError::ObservedResponseClosed)?;
+            }
+            Err(error) => request = error.0.request,
+        }
+    }
+    let (response_tx, response_rx) = oneshot::channel();
+    senders
+        .receipt
+        .send(HealReceiptCommand { request, response_tx })
+        .map_err(|_| HealObservationChannelError::LegacyCommandClosed)?;
+    let receipt = response_rx
+        .await
+        .map_err(HealObservationChannelError::LegacyResponseClosed)?
+        .map_err(HealObservationChannelError::AdmissionFailed)?;
+    Ok(ObservedHealAdmissionReceipt {
+        receipt,
+        observation_id: None,
+    })
+}
+
 /// Send heal start request and wait for structured admission feedback.
 pub async fn send_heal_request_with_admission(request: HealChannelRequest) -> Result<HealAdmissionResult, String> {
     let (response_tx, response_rx) = oneshot::channel();
@@ -775,6 +884,109 @@ mod auto_heal_disk_request_tests {
 mod tests {
     use super::*;
 
+    #[tokio::test]
+    async fn observed_receipt_falls_back_only_when_no_observed_command_was_accepted() {
+        for closed in [false, true] {
+            let (command, _command_rx) = mpsc::unbounded_channel();
+            let (receipt, mut receipt_rx) = mpsc::unbounded_channel();
+            let observed = if closed {
+                let (sender, receiver) = mpsc::unbounded_channel();
+                drop(receiver);
+                Some(sender)
+            } else {
+                None
+            };
+            let senders = HealChannelSenders {
+                command,
+                receipt,
+                observed,
+            };
+            let request = HealChannelRequest::new();
+            let task = tokio::spawn(async move { send_heal_request_with_observation_on(&senders, request).await });
+            let command = receipt_rx.recv().await.expect("legacy receipt command");
+            command
+                .response_tx
+                .send(Ok(HealAdmissionReceipt {
+                    result: HealAdmissionResult::Accepted,
+                    task_id: "owner".into(),
+                }))
+                .expect("caller waiting");
+            let received = task.await.expect("sender task").expect("legacy admission");
+            assert_eq!(received.task_id, "owner");
+            assert_eq!(received.observation_id, None);
+        }
+    }
+
+    #[tokio::test]
+    async fn lost_observed_reply_never_resends_the_request() {
+        let (command, _command_rx) = mpsc::unbounded_channel();
+        let (receipt, mut receipt_rx) = mpsc::unbounded_channel();
+        let keep_receipt_open = receipt.clone();
+        let (observed, mut observed_rx) = mpsc::unbounded_channel();
+        let senders = HealChannelSenders {
+            command,
+            receipt,
+            observed: Some(observed),
+        };
+        let task = tokio::spawn(async move { send_heal_request_with_observation_on(&senders, HealChannelRequest::new()).await });
+        let command = observed_rx.recv().await.expect("accepted observed command");
+        drop(command.response_tx);
+        let error = task
+            .await
+            .expect("sender task")
+            .expect_err("lost response must remain an error");
+        assert!(matches!(&error, HealObservationChannelError::ObservedResponseClosed(_)));
+        assert!(std::error::Error::source(&error).is_some());
+        assert!(matches!(receipt_rx.try_recv(), Err(mpsc::error::TryRecvError::Empty)));
+        drop(keep_receipt_open);
+    }
+
+    #[tokio::test]
+    async fn fallback_reports_a_typed_error_if_legacy_channel_is_closed() {
+        let (command, _command_rx) = mpsc::unbounded_channel();
+        let (receipt, receipt_rx) = mpsc::unbounded_channel();
+        drop(receipt_rx);
+        let senders = HealChannelSenders {
+            command,
+            receipt,
+            observed: None,
+        };
+        let error = send_heal_request_with_observation_on(&senders, HealChannelRequest::new())
+            .await
+            .expect_err("closed legacy channel must not accept work");
+        assert!(matches!(error, HealObservationChannelError::LegacyCommandClosed));
+    }
+
+    #[tokio::test]
+    async fn observed_receipt_keeps_the_owner_token_from_the_processor() {
+        let (command, _command_rx) = mpsc::unbounded_channel();
+        let (receipt, mut receipt_rx) = mpsc::unbounded_channel();
+        let keep_receipt_open = receipt.clone();
+        let (observed, mut observed_rx) = mpsc::unbounded_channel();
+        let senders = HealChannelSenders {
+            command,
+            receipt,
+            observed: Some(observed),
+        };
+        let task = tokio::spawn(async move { send_heal_request_with_observation_on(&senders, HealChannelRequest::new()).await });
+        let command = observed_rx.recv().await.expect("observed command");
+        command
+            .response_tx
+            .send(Ok(ObservedHealAdmissionReceipt {
+                receipt: HealAdmissionReceipt {
+                    result: HealAdmissionResult::Merged,
+                    task_id: "owner".into(),
+                },
+                observation_id: Some(37),
+            }))
+            .expect("caller waiting");
+        let received = task.await.expect("sender task").expect("observed admission");
+        assert_eq!(received.task_id, "owner");
+        assert_eq!(received.observation_id, Some(37));
+        assert!(matches!(receipt_rx.try_recv(), Err(mpsc::error::TryRecvError::Empty)));
+        drop(keep_receipt_open);
+    }
+
     #[test]
     fn heal_request_source_labels_are_stable() {
         assert_eq!(HealRequestSource::Scanner.as_str(), "scanner");

crates/heal/src/heal/channel.rs

@@ -21,8 +21,8 @@ use crate::heal::{
 use crate::{Error, Result};
 use rustfs_heal_contracts::heal_channel::{
     HealAdmissionReceipt, HealAdmissionResult, HealChannelCommand, HealChannelPriority, HealChannelReceiver, HealChannelRequest,
-    HealChannelResponse, HealOpts, HealReceiptCommand, HealReceiptReceiver, HealRequestSource, HealScanMode,
-    publish_heal_response,
+    HealChannelResponse, HealObservationChannelError, HealOpts, HealReceiptCommand, HealReceiptReceiver, HealRequestSource,
+    HealScanMode, ObservedHealAdmissionReceipt, ObservedHealReceiptCommand, ObservedHealReceiptReceiver, publish_heal_response,
 };
 use rustfs_madmin::heal_commands::HealResultItem;
 use serde::Serialize;
@@ -30,6 +30,24 @@ use std::sync::Arc;
 use tokio::sync::{mpsc, oneshot};
 use tracing::{debug, error, info};
 
+enum StartResponseSender {
+    Legacy(oneshot::Sender<std::result::Result<HealAdmissionReceipt, String>>),
+    Observed(oneshot::Sender<std::result::Result<ObservedHealAdmissionReceipt, HealObservationChannelError>>),
+}
+
+impl StartResponseSender {
+    fn send(self, result: std::result::Result<ObservedHealAdmissionReceipt, String>) {
+        match self {
+            Self::Legacy(sender) => {
+                let _ = sender.send(result.map(|observed| observed.receipt));
+            }
+            Self::Observed(sender) => {
+                let _ = sender.send(result.map_err(HealObservationChannelError::AdmissionFailed));
+            }
+        }
+    }
+}
+
 const LOG_COMPONENT_HEAL: &str = "heal";
 const LOG_SUBSYSTEM_CHANNEL: &str = "channel";
 const EVENT_HEAL_CHANNEL_STATE: &str = "heal_channel_state";
@@ -215,9 +233,22 @@ impl HealChannelProcessor {
 
     /// Start processing legacy and canonical-receipt heal channel requests.
     pub async fn start_with_receipts(
+        &mut self,
+        receiver: HealChannelReceiver,
+        receipt_receiver: HealReceiptReceiver,
+    ) -> Result<()> {
+        let (sender, receiver_observed) = mpsc::unbounded_channel();
+        drop(sender);
+        self.start_with_observed_receipts(receiver, receipt_receiver, receiver_observed)
+            .await
+    }
+
+    /// The three command channels are FIFO independently, with no ordering across channels.
+    pub async fn start_with_observed_receipts(
         &mut self,
         mut receiver: HealChannelReceiver,
         mut receipt_receiver: HealReceiptReceiver,
+        mut observed_receiver: ObservedHealReceiptReceiver,
     ) -> Result<()> {
         info!(
             target: "rustfs::heal::channel",
@@ -229,6 +260,7 @@ impl HealChannelProcessor {
         );
 
         let mut receipt_channel_open = true;
+        let mut observed_channel_open = true;
         loop {
             tokio::select! {
                 command = receiver.recv() => {
@@ -276,6 +308,23 @@ impl HealChannelProcessor {
                         );
                     }
                 }
+                command = observed_receiver.recv(), if observed_channel_open => {
+                    let Some(ObservedHealReceiptCommand { request, response_tx }) = command else {
+                        observed_channel_open = false;
+                        continue;
+                    };
+                    if let Err(e) = self.process_start_request_inner(request, false, true, StartResponseSender::Observed(response_tx)).await {
+                        error!(
+                            target: "rustfs::heal::channel",
+                            event = EVENT_HEAL_CHANNEL_REQUEST,
+                            component = LOG_COMPONENT_HEAL,
+                            subsystem = LOG_SUBSYSTEM_CHANNEL,
+                            state = "receipt_process_failed",
+                            error = %e,
+                            "Heal receipt request processing failed"
+                        );
+                    }
+                }
                 response = self.response_receiver.recv() => {
                     if let Some(response) = response {
                         // Handle response if needed
@@ -344,10 +393,21 @@ impl HealChannelProcessor {
     /// Process start request
     async fn process_start_request(
         &self,
-        mut request: HealChannelRequest,
+        request: HealChannelRequest,
         preserve_alias: bool,
         publish_canonical_id: bool,
         response_tx: oneshot::Sender<std::result::Result<HealAdmissionReceipt, String>>,
+    ) -> Result<()> {
+        self.process_start_request_inner(request, preserve_alias, publish_canonical_id, StartResponseSender::Legacy(response_tx))
+            .await
+    }
+
+    async fn process_start_request_inner(
+        &self,
+        mut request: HealChannelRequest,
+        preserve_alias: bool,
+        publish_canonical_id: bool,
+        response_tx: StartResponseSender,
     ) -> Result<()> {
         if request.id.is_empty() {
             request.id = uuid::Uuid::new_v4().to_string();
@@ -369,7 +429,7 @@ impl HealChannelProcessor {
             Ok(heal_request) => heal_request,
             Err(err) => {
                 let error_text = err.to_string();
-                let _ = response_tx.send(Err(error_text.clone()));
+                response_tx.send(Err(error_text.clone()));
                 self.publish_response(HealChannelResponse {
                     request_id: request.id,
                     success: false,
@@ -383,7 +443,7 @@ impl HealChannelProcessor {
         // Submit to heal manager
         match self
             .heal_manager
-            .submit_heal_request_with_receipt_and_alias(heal_request, preserve_alias)
+            .submit_heal_request_with_observation_and_alias(heal_request, preserve_alias)
             .await
         {
             Ok(receipt) => {
@@ -405,7 +465,7 @@ impl HealChannelProcessor {
                     request.id.clone()
                 };
                 self.publish_response(admission_response(response_id, receipt.result));
-                let _ = response_tx.send(Ok(receipt));
+                response_tx.send(Ok(receipt));
             }
             Err(e) => {
                 let error_text = e.to_string();
@@ -419,7 +479,7 @@ impl HealChannelProcessor {
                     error = %error_text,
                     "Heal start submission failed"
                 );
-                let _ = response_tx.send(Err(error_text.clone()));
+                response_tx.send(Err(error_text.clone()));
 
                 // Send error response
                 let response = HealChannelResponse {
@@ -1748,6 +1808,84 @@ mod tests {
             .expect("legacy alias should cancel the canonical task");
     }
 
+    #[tokio::test]
+    async fn observed_and_legacy_channels_share_the_real_admission_owner() {
+        let manager = create_test_heal_manager();
+        let mut processor = HealChannelProcessor::new(manager);
+        let (command_tx, command_rx) = mpsc::unbounded_channel();
+        let (receipt_tx, receipt_rx) = mpsc::unbounded_channel();
+        let (observed_tx, observed_rx) = mpsc::unbounded_channel();
+        let task = tokio::spawn(async move {
+            processor
+                .start_with_observed_receipts(command_rx, receipt_rx, observed_rx)
+                .await
+        });
+        let request = HealChannelRequest {
+            id: "observed-owner".into(),
+            bucket: "observed-owner-bucket".into(),
+            object_prefix: Some("object".into()),
+            source: HealRequestSource::Internal,
+            ..Default::default()
+        };
+        let (response_tx, response_rx) = oneshot::channel();
+        observed_tx
+            .send(ObservedHealReceiptCommand {
+                request: request.clone(),
+                response_tx,
+            })
+            .expect("observed command");
+        let first = tokio::time::timeout(Duration::from_secs(1), response_rx)
+            .await
+            .expect("observed response")
+            .expect("sender")
+            .expect("admitted");
+        assert_eq!(first.result, HealAdmissionResult::Accepted);
+        assert!(first.observation_id.is_some());
+
+        let mut duplicate = request.clone();
+        duplicate.id = "legacy-observed-duplicate".into();
+        let (response_tx, response_rx) = oneshot::channel();
+        receipt_tx
+            .send(HealReceiptCommand {
+                request: duplicate,
+                response_tx,
+            })
+            .expect("legacy command");
+        let legacy = tokio::time::timeout(Duration::from_secs(1), response_rx)
+            .await
+            .expect("legacy response")
+            .expect("sender")
+            .expect("merged");
+        assert_eq!(legacy.result, HealAdmissionResult::Merged);
+        assert_eq!(legacy.task_id, first.task_id);
+
+        let mut duplicate = request;
+        duplicate.id = "observed-duplicate".into();
+        let (response_tx, response_rx) = oneshot::channel();
+        observed_tx
+            .send(ObservedHealReceiptCommand {
+                request: duplicate,
+                response_tx,
+            })
+            .expect("observed duplicate");
+        let merged = tokio::time::timeout(Duration::from_secs(1), response_rx)
+            .await
+            .expect("observed response")
+            .expect("sender")
+            .expect("merged");
+        assert_eq!(merged.result, HealAdmissionResult::Merged);
+        assert_eq!(merged.task_id, first.task_id);
+        assert_eq!(merged.observation_id, first.observation_id);
+        drop(command_tx);
+        assert!(
+            tokio::time::timeout(Duration::from_secs(1), task)
+                .await
+                .expect("processor stops")
+                .expect("join")
+                .is_ok()
+        );
+    }
+
     #[tokio::test]
     async fn test_public_legacy_start_processes_commands_with_receipt_channel_closed() {
         let manager = create_test_heal_manager();

crates/heal/src/heal/manager.rs

@@ -29,7 +29,7 @@ use rustfs_concurrency::workload::{ForegroundPressure, foreground_pressure};
 #[cfg(test)]
 use rustfs_concurrency::{AdmissionState, WorkloadClass};
 use rustfs_heal_contracts::heal_channel::{
-    HealAdmissionDropReason, HealAdmissionReceipt, HealAdmissionResult, HealRequestSource,
+    HealAdmissionDropReason, HealAdmissionReceipt, HealAdmissionResult, HealRequestSource, ObservedHealAdmissionReceipt,
 };
 use rustfs_madmin::heal_commands::HealResultItem;
 #[cfg(test)]
@@ -297,6 +297,7 @@ async fn publish_completed_heal(
     task_id: &str,
     completed: CompletedHealStatus,
     terminal: bool,
+    observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
 ) {
     let completed = Arc::new(completed);
     completed.retained_bytes();
@@ -328,13 +329,16 @@ async fn publish_completed_heal(
                 identity: object.identity.clone(),
                 disposition: object.disposition.clone(),
             });
-        rustfs_heal_contracts::completion::publish_heal_completion(rustfs_heal_contracts::completion::HealCompletion {
-            task_id: task_id.to_owned(),
-            scan_mode: completed.options.scan_mode,
-            dry_run: completed.options.dry_run,
-            execution: outcome.map(|outcome| outcome.execution),
-            object,
-        });
+        rustfs_heal_contracts::completion::publish_observed_heal_completion(
+            rustfs_heal_contracts::completion::HealCompletion {
+                task_id: task_id.to_owned(),
+                scan_mode: completed.options.scan_mode,
+                dry_run: completed.options.dry_run,
+                execution: outcome.map(|outcome| outcome.execution),
+                object,
+            },
+            observation_id,
+        );
     }
 }
 
@@ -625,6 +629,38 @@ fn request_matches_request(request: &HealRequest, existing: &HealRequest) -> boo
         && request.heal_endpoints == existing.heal_endpoints
 }
 
+fn lookup_request_id_admission(
+    request: &HealRequest,
+    active_heals: &HashMap<String, Arc<HealTask>>,
+    queue: &PriorityHealQueue,
+    retrying_heals: &HashMap<String, RetryingHeal>,
+    durable_owners: &[HealRequest],
+) -> Option<(bool, &'static str, Option<rustfs_heal_contracts::completion::HealObservationId>)> {
+    active_heals
+        .get(&request.id)
+        .map(|task| (request_matches_task(request, task), "active", task.observation_id))
+        .or_else(|| {
+            // A request ID can name multiple queued sequences; the token is unknown.
+            queue
+                .requests()
+                .find(|queued| queued.id == request.id)
+                .map(|queued| (request_matches_request(request, queued), "queued", None))
+        })
+        .or_else(|| {
+            retrying_heals
+                .get(&request.id)
+                .map(|retrying| (request_matches_request(request, &retrying.request), "retrying", retrying.observation_id))
+        })
+        // A durable-only owner must be resumed by recovery, not overwritten
+        // with a new execution budget by a replay before recovery completes.
+        .or_else(|| {
+            durable_owners
+                .iter()
+                .find(|owner| owner.id == request.id)
+                .map(|_| (false, "durable", None))
+        })
+}
+
 fn retrying_heal_for_dedup_key(retrying_heals: &HashMap<String, RetryingHeal>, key: &str) -> Option<(String, HealType)> {
     retrying_heals
         .iter()
@@ -1292,6 +1328,7 @@ impl HealManager {
         config: &HealConfig,
         context: &'static str,
         replacement_targets_frozen: bool,
+        observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
     ) -> HealAdmissionDecision {
         let replacement_targets_frozen = replacement_targets_frozen || request.retry_attempts != 0;
         let queue_len = queue.len();
@@ -1328,7 +1365,7 @@ impl HealManager {
                 let priority = request.priority;
                 let source = request.source;
                 if let Some(displaced) =
-                    queue.push_displacing_lower_priority_where(request, Self::queued_request_can_be_displaced)
+                    queue.push_displacing_lower_priority_where(request, Self::queued_request_can_be_displaced, observation_id)
                 {
                     publish_heal_queue_length(queue);
                     Self::record_admission_metric(source, HealAdmissionResult::Accepted, context);
@@ -1479,7 +1516,7 @@ impl HealManager {
         let priority = request.priority;
         let source = request.source;
 
-        match queue.push_with_replacement_scope(request, replacement_targets_frozen) {
+        match queue.push_with_replacement_scope(request, replacement_targets_frozen, observation_id) {
             QueuePushOutcome::Accepted => {
                 publish_heal_queue_length(queue);
                 Self::record_admission_metric(source, HealAdmissionResult::Accepted, context);
@@ -1951,6 +1988,17 @@ impl HealManager {
         request: HealRequest,
         preserve_alias: bool,
     ) -> Result<HealAdmissionReceipt> {
+        Ok(self
+            .submit_heal_request_with_observation_and_alias(request, preserve_alias)
+            .await?
+            .receipt)
+    }
+
+    pub(crate) async fn submit_heal_request_with_observation_and_alias(
+        &self,
+        request: HealRequest,
+        preserve_alias: bool,
+    ) -> Result<ObservedHealAdmissionReceipt> {
         self.submit_heal_request_with_receipt_alias_and_mrf_notice(request, preserve_alias, true, None)
             .await
     }
@@ -1991,8 +2039,10 @@ impl HealManager {
         mrf_notice_target: MrfRepairNoticeTarget,
     ) -> Result<HealAdmissionReceipt> {
         let preserve_alias = !mrf_notice_target.kind.is_durable();
-        self.submit_heal_request_with_receipt_alias_and_mrf_notice(request, preserve_alias, true, Some(mrf_notice_target))
-            .await
+        Ok(self
+            .submit_heal_request_with_receipt_alias_and_mrf_notice(request, preserve_alias, true, Some(mrf_notice_target))
+            .await?
+            .receipt)
     }
 
     #[cfg(test)]
@@ -2058,7 +2108,7 @@ impl HealManager {
         preserve_alias: bool,
         accept_same_request_id_replay: bool,
         mrf_notice_target: Option<MrfRepairNoticeTarget>,
-    ) -> Result<HealAdmissionReceipt> {
+    ) -> Result<ObservedHealAdmissionReceipt> {
         let admission_start = Instant::now();
         if request.id.is_empty() {
             request.id = uuid::Uuid::new_v4().to_string();
@@ -2119,77 +2169,10 @@ impl HealManager {
         let mut queue = self.heal_queue.lock().await;
         let mut retrying_heals = self.retrying_heals.lock().await;
 
-        let request_id_admission = active_heals
-            .get(&request.id)
-            .map(|task| (request_matches_task(&request, task), "active"))
-            .or_else(|| {
-                queue
-                    .requests()
-                    .find(|queued| queued.id == request.id)
-                    .map(|queued| (request_matches_request(&request, queued), "queued"))
-            })
-            .or_else(|| {
-                retrying_heals
-                    .get(&request.id)
-                    .map(|retrying| (request_matches_request(&request, &retrying.request), "retrying"))
-            })
-            // A durable-only owner must be resumed by recovery, not overwritten
-            // with a new execution budget by a replay before recovery completes.
-            .or_else(|| {
-                durable_owners
-                    .iter()
-                    .find(|owner| owner.id == request.id)
-                    .map(|_| (false, "durable"))
-            });
-        if let Some((matches_existing, duplicate_state)) = request_id_admission {
-            let admission = if matches_existing {
-                if accept_same_request_id_replay {
-                    HealAdmissionResult::Accepted
-                } else {
-                    Self::duplicate_admission_for_request(&request, &config)
-                }
-            } else {
-                HealAdmissionResult::Dropped(HealAdmissionDropReason::AlreadyRunning)
-            };
-            if matches!(admission, HealAdmissionResult::Accepted | HealAdmissionResult::Merged)
-                && let Some(target) = mrf_notice_target
-            {
-                let mut targets = lock_mrf_repair_notice_targets(&self.mrf_repair_notice_targets);
-                Self::insert_mrf_repair_notice_target(&mut targets, &request.id, target);
-            }
-            drop(retrying_heals);
-            drop(queue);
-            drop(active_heals);
-            let lock_timing =
-                HealAdmissionLockTiming::finish(lock_phase_start, active_lock_acquired, active_lock_wait, active_lock_hold);
-            Self::record_admission_metric(request.source, admission, "duplicate");
-            self.record_admission_observation(HealAdmissionObservation {
-                source,
-                result: admission,
-                context: "duplicate",
-                force_start,
-                displaced: false,
-                start_duration: admission_start.elapsed(),
-                lock_timing,
-            });
-            debug!(
-                target: "rustfs::heal::manager",
-                event = EVENT_HEAL_QUEUE_ADMISSION,
-                component = LOG_COMPONENT_HEAL,
-                subsystem = LOG_SUBSYSTEM_MANAGER,
-                request_id = %request.id,
-                duplicate_state,
-                result = admission.result_label(),
-                reason = admission.reason_label(),
-                "Heal queue admission reused an existing request id"
-            );
-            return Ok(HealAdmissionReceipt {
-                result: admission,
-                task_id: request.id,
-            });
-        }
+        let mut request_id_admission =
+            lookup_request_id_admission(&request, &active_heals, &queue, &retrying_heals, &durable_owners);
 
-        if source == HealRequestSource::Admin && force_start {
+        if request_id_admission.is_none() && source == HealRequestSource::Admin && force_start {
             let overlapping = active_heals
                 .values()
                 .map(|task| (&task.id, &task.heal_type, &task.options, task.source))
@@ -2235,6 +2218,59 @@ impl HealManager {
             active_lock_wait += active_lock_acquired.duration_since(reacquire_start);
             queue = self.heal_queue.lock().await;
             retrying_heals = self.retrying_heals.lock().await;
+            // Non-admin admission can claim this id while cancellation drops the state locks.
+            request_id_admission = lookup_request_id_admission(&request, &active_heals, &queue, &retrying_heals, &durable_owners);
+        }
+
+        if let Some((matches_existing, duplicate_state, observation_id)) = request_id_admission {
+            let admission = if matches_existing {
+                if accept_same_request_id_replay {
+                    HealAdmissionResult::Accepted
+                } else {
+                    Self::duplicate_admission_for_request(&request, &config)
+                }
+            } else {
+                HealAdmissionResult::Dropped(HealAdmissionDropReason::AlreadyRunning)
+            };
+            if matches!(admission, HealAdmissionResult::Accepted | HealAdmissionResult::Merged)
+                && let Some(target) = mrf_notice_target
+            {
+                let mut targets = lock_mrf_repair_notice_targets(&self.mrf_repair_notice_targets);
+                Self::insert_mrf_repair_notice_target(&mut targets, &request.id, target);
+            }
+            drop(retrying_heals);
+            drop(queue);
+            drop(active_heals);
+            let lock_timing =
+                HealAdmissionLockTiming::finish(lock_phase_start, active_lock_acquired, active_lock_wait, active_lock_hold);
+            Self::record_admission_metric(request.source, admission, "duplicate");
+            self.record_admission_observation(HealAdmissionObservation {
+                source,
+                result: admission,
+                context: "duplicate",
+                force_start,
+                displaced: false,
+                start_duration: admission_start.elapsed(),
+                lock_timing,
+            });
+            debug!(
+                target: "rustfs::heal::manager",
+                event = EVENT_HEAL_QUEUE_ADMISSION,
+                component = LOG_COMPONENT_HEAL,
+                subsystem = LOG_SUBSYSTEM_MANAGER,
+                request_id = %request.id,
+                duplicate_state,
+                result = admission.result_label(),
+                reason = admission.reason_label(),
+                "Heal queue admission reused an existing request id"
+            );
+            return Ok(ObservedHealAdmissionReceipt {
+                receipt: HealAdmissionReceipt {
+                    result: admission,
+                    task_id: request.id,
+                },
+                observation_id,
+            });
         }
 
         let rejection = if source == HealRequestSource::Admin {
@@ -2282,26 +2318,45 @@ impl HealManager {
             None
         };
 
+        let scanner_queued_owner_required = request.source == HealRequestSource::Scanner
+            && mrf_notice_target.is_none()
+            && request.expected_mrf_bucket_incarnation_id.is_none();
         let duplicate = (!request.force_start && rejection.is_none()).then(|| {
             active_heal_for_dedup_key(&active_heals, &dedup_key)
-                .map(|(task_id, _)| (task_id, "active"))
-                .or_else(|| {
-                    queue
-                        .queued_request_id_for_dedup_key(&dedup_key)
-                        .map(|queued_id| (queued_id.to_string(), "queued"))
+                .map(|(task_id, _)| {
+                    let observation_id = active_heals.get(&task_id).and_then(|task| task.observation_id);
+                    (task_id, "active", observation_id)
+                })
+                .or_else(|| {
+                    let owner = if scanner_queued_owner_required {
+                        queue.queued_scanner_owner_for_dedup_key(&dedup_key)
+                    } else {
+                        queue.queued_legacy_owner_for_dedup_key(&dedup_key)
+                    };
+                    owner
+                        .map(|(id, observation_id)| (id.to_string(), "queued", observation_id))
+                        .or_else(|| {
+                            (scanner_queued_owner_required && queue.dedup_keys.contains_key(&dedup_key))
+                                .then(|| (request.id.clone(), "queued_owner_unknown", None))
+                        })
+                })
+                .or_else(|| {
+                    retrying_heal_for_dedup_key(&retrying_heals, &dedup_key).map(|(task_id, _)| {
+                        let observation_id = retrying_heals.get(&task_id).and_then(|retry| retry.observation_id);
+                        (task_id, "retrying", observation_id)
+                    })
                 })
-                .or_else(|| retrying_heal_for_dedup_key(&retrying_heals, &dedup_key).map(|(task_id, _)| (task_id, "retrying")))
         });
-        if let Some((merged_task_id, duplicate_state)) = duplicate.flatten() {
+        if let Some((merged_task_id, duplicate_state, observation_id)) = duplicate.flatten() {
             // HS-06: under the minio_error overlap policy an exact duplicate
             // admin start reports the typed AlreadyRunning rejection instead
             // of the silent merge (MinIO's ErrHealAlreadyRunning).
-            let mut admission = if (request.source == HealRequestSource::Admin
-                && config.overlap_policy == HealOverlapPolicy::MinioError)
+            let mut admission = if duplicate_state == "queued_owner_unknown"
+                || (request.source == HealRequestSource::Admin && config.overlap_policy == HealOverlapPolicy::MinioError)
                 || (duplicate_state != "queued" && mrf_notice_target.as_ref().is_some_and(|target| target.kind.is_durable()))
             {
-                // A running/retrying task may have observed the object before
-                // this write committed. Its receipt cannot prove the new lease.
+                // An unknown queued owner cannot certify a receipt. A running or
+                // retrying task may have observed the object before this write.
                 HealAdmissionResult::Dropped(HealAdmissionDropReason::AlreadyRunning)
             } else {
                 Self::duplicate_admission_for_request(&request, &config)
@@ -2400,9 +2455,12 @@ impl HealManager {
                 HealAdmissionResult::Accepted | HealAdmissionResult::Full => {}
             }
 
-            return Ok(HealAdmissionReceipt {
-                result: admission,
-                task_id: merged_task_id,
+            return Ok(ObservedHealAdmissionReceipt {
+                receipt: HealAdmissionReceipt {
+                    result: admission,
+                    task_id: merged_task_id,
+                },
+                observation_id,
             });
         }
 
@@ -2433,9 +2491,12 @@ impl HealManager {
                 result = "overlap_rejected",
                 "Admin heal start rejected by overlap policy"
             );
-            return Ok(HealAdmissionReceipt {
-                result: HealAdmissionResult::Dropped(reason),
-                task_id: overlap_task_id,
+            return Ok(ObservedHealAdmissionReceipt {
+                receipt: HealAdmissionReceipt {
+                    result: HealAdmissionResult::Dropped(reason),
+                    task_id: overlap_task_id,
+                },
+                observation_id: None,
             });
         }
 
@@ -2477,9 +2538,12 @@ impl HealManager {
                     result = "dropped_by_disposition",
                     "Heal queue admission answered from the disposition memory"
                 );
-                return Ok(HealAdmissionReceipt {
-                    result: admission,
-                    task_id: recorded_task_id,
+                return Ok(ObservedHealAdmissionReceipt {
+                    receipt: HealAdmissionReceipt {
+                        result: admission,
+                        task_id: recorded_task_id,
+                    },
+                    observation_id: None,
                 });
             }
         }
@@ -2507,17 +2571,31 @@ impl HealManager {
                 .lock()
                 .unwrap_or_else(|poisoned| poisoned.into_inner())
                 .contains_key(&request.id);
-        let admission_decision = Self::admit_request_to_queue(&mut queue, request, &config, "submit", recovered_replacement);
+        let mut observation_id = rustfs_heal_contracts::completion::new_heal_observation_id();
+        let admission_decision =
+            Self::admit_request_to_queue(&mut queue, request, &config, "submit", recovered_replacement, observation_id);
         let admission = admission_decision.result;
         if durable_handoff_required && !admission.is_admitted() {
             self.root_recovery
                 .remove(&request_id, &request_heal_type, request_source)
                 .await?;
         }
-        if admission == HealAdmissionResult::Merged
-            && let Some(queued_id) = queue.queued_request_id_for_dedup_key(&dedup_key)
-        {
-            task_id = queued_id.to_owned();
+        if admission == HealAdmissionResult::Merged {
+            observation_id = None;
+            let owner = if scanner_queued_owner_required {
+                queue.queued_scanner_owner_for_dedup_key(&dedup_key)
+            } else {
+                queue.queued_legacy_owner_for_dedup_key(&dedup_key)
+            };
+            if let Some((id, owner_observation_id)) = owner {
+                task_id = id.to_owned();
+                observation_id = owner_observation_id;
+            } else if scanner_queued_owner_required {
+                return Err(Error::Other("Scanner queued owner is unavailable".to_owned()));
+            }
+        }
+        if !admission.is_admitted() {
+            observation_id = None;
         }
         let should_notify = matches!(admission, HealAdmissionResult::Accepted) && config.event_driven_scheduler_enable;
         let displaced_task_id = admission_decision.displaced_task_id().map(ToOwned::to_owned);
@@ -2563,9 +2641,12 @@ impl HealManager {
             lock_timing,
         });
 
-        Ok(HealAdmissionReceipt {
-            result: admission,
-            task_id,
+        Ok(ObservedHealAdmissionReceipt {
+            receipt: HealAdmissionReceipt {
+                result: admission,
+                task_id,
+            },
+            observation_id,
         })
     }
 
@@ -2887,7 +2968,15 @@ impl HealManager {
                     .await?;
                 self.root_recovery.remove(&task.id, &task.heal_type, task.source).await?;
                 task.cancel().await?;
-                publish_completed_heal(&self.completed_heals, &self.task_aliases, &canonical_task_id, completed, true).await;
+                publish_completed_heal(
+                    &self.completed_heals,
+                    &self.task_aliases,
+                    &canonical_task_id,
+                    completed,
+                    true,
+                    task.observation_id,
+                )
+                .await;
                 active_heals.remove(&canonical_task_id);
                 publish_active_heal_count(&active_heals);
                 info!(
@@ -2998,7 +3087,15 @@ impl HealManager {
                         .await?;
                     self.root_recovery.remove(&task.id, &task.heal_type, task.source).await?;
                     task.cancel().await?;
-                    publish_completed_heal(&self.completed_heals, &self.task_aliases, task_id, completed, true).await;
+                    publish_completed_heal(
+                        &self.completed_heals,
+                        &self.task_aliases,
+                        task_id,
+                        completed,
+                        true,
+                        task.observation_id,
+                    )
+                    .await;
                 }
                 active_heals.remove(task_id);
                 cancelled += 1;

crates/heal/src/heal/manager/auto_scan.rs

@@ -693,7 +693,7 @@ impl HealManager {
                             let config = config.read().await;
                             let mut queue = heal_queue.lock().await;
                             let admission_decision =
-                                Self::admit_request_to_queue(&mut queue, req, &config, "auto_scan", recovered_replacement);
+                                Self::admit_request_to_queue(&mut queue, req, &config, "auto_scan", recovered_replacement, rustfs_heal_contracts::completion::new_heal_observation_id());
                             let admission = admission_decision.result;
                             let should_notify =
                                 matches!(admission, HealAdmissionResult::Accepted) && config.event_driven_scheduler_enable;

crates/heal/src/heal/manager/queue.rs

@@ -13,15 +13,31 @@
 // limitations under the License.
 /// The priority heal queue and its per-key dedup index.
 use super::*;
+use std::collections::BTreeMap;
 
-/// Per-key bookkeeping for the queued-request dedup index: how many queued
-/// requests hold the key, and the id of the first request that opened it —
-/// the O(1) stand-in for the former heap scan when a merge receipt needs to
-/// name a queued representative.
+/// Per-key bookkeeping for the queued-request dedup index. The legacy
+/// representative is retained for existing non-scanner callers; scanner
+/// receipts use the separately tracked queued holders.
 #[derive(Debug)]
 pub(super) struct DedupKeyEntry {
     pub(super) refcount: usize,
     pub(super) representative_request_id: String,
+    representative_sequence: u64,
+    representative_observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
+    pub(super) scanner_queued_owners: ScannerQueuedOwners,
+}
+
+#[derive(Debug)]
+pub(super) struct QueuedOwner {
+    request_id: String,
+    observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
+}
+
+#[derive(Debug)]
+pub(super) enum ScannerQueuedOwners {
+    Single(u64),
+    // Once a key has forced duplicates, keep every live holder until it is released.
+    Indexed(BTreeMap<u64, QueuedOwner>),
 }
 
 /// Priority queue wrapper for heal requests
@@ -70,10 +86,25 @@ pub(super) struct PriorityQueueItem {
     pub(super) sequence: u64,
     pub(super) dedup_key: String,
     pub(super) request: HealRequest,
+    observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
     /// Execution or durable recovery fixed these targets; grace waits can have zero retries.
     pub(super) replacement_targets_frozen: bool,
 }
 
+/// The in-process identity moves with the queue item, including forced duplicates.
+pub(super) struct QueuedHeal {
+    pub(super) request: HealRequest,
+    pub(super) observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
+}
+
+impl std::ops::Deref for QueuedHeal {
+    type Target = HealRequest;
+
+    fn deref(&self) -> &Self::Target {
+        &self.request
+    }
+}
+
 impl Eq for PriorityQueueItem {}
 
 impl PartialEq for PriorityQueueItem {
@@ -283,6 +314,7 @@ pub(super) struct HealTaskAlias {
 #[derive(Debug, Clone)]
 pub(super) struct RetryingHeal {
     pub(super) request: HealRequest,
+    pub(super) observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
     pub(super) error: String,
     pub(super) cancel_token: CancellationToken,
 }
@@ -306,11 +338,7 @@ impl PriorityHealQueue {
 
     #[cfg(test)]
     pub(super) fn pop_next(&mut self) -> Option<HealRequest> {
-        self.heap.pop().map(|item| {
-            Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item.dedup_key);
-            self.remove_best_effort_count(item.request.source);
-            item.request
-        })
+        self.heap.pop().map(|item| self.remove_queued_item(item).request)
     }
 
     pub(super) fn is_empty(&self) -> bool {
@@ -318,10 +346,15 @@ impl PriorityHealQueue {
     }
 
     pub(super) fn push(&mut self, request: HealRequest) -> QueuePushOutcome {
-        self.push_with_replacement_scope(request, false)
+        self.push_with_replacement_scope(request, false, rustfs_heal_contracts::completion::new_heal_observation_id())
     }
 
-    pub(super) fn push_with_replacement_scope(&mut self, request: HealRequest, frozen: bool) -> QueuePushOutcome {
+    pub(super) fn push_with_replacement_scope(
+        &mut self,
+        request: HealRequest,
+        frozen: bool,
+        observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
+    ) -> QueuePushOutcome {
         let key = Self::make_dedup_key(&request);
 
         // Check for duplicates unless the caller explicitly forces admission.
@@ -332,20 +365,60 @@ impl PriorityHealQueue {
         // also reserves the dedup key for later non-forced duplicates. The first
         // request that opens the key becomes the named representative for merge
         // receipts (taken before `request` moves into the heap).
-        self.dedup_keys
-            .entry(key.clone())
-            .or_insert_with(|| DedupKeyEntry {
-                refcount: 0,
-                representative_request_id: request.id.clone(),
-            })
-            .refcount += 1;
         self.sequence += 1;
+        let sequence = self.sequence;
+        if let Some(entry) = self.dedup_keys.get_mut(&key) {
+            match &mut entry.scanner_queued_owners {
+                ScannerQueuedOwners::Single(first_sequence) => {
+                    let mut owners = BTreeMap::new();
+                    if entry.refcount == 1 && entry.representative_sequence == *first_sequence {
+                        owners.insert(
+                            *first_sequence,
+                            QueuedOwner {
+                                request_id: entry.representative_request_id.clone(),
+                                observation_id: entry.representative_observation_id,
+                            },
+                        );
+                    }
+                    owners.insert(
+                        sequence,
+                        QueuedOwner {
+                            request_id: request.id.clone(),
+                            observation_id,
+                        },
+                    );
+                    entry.scanner_queued_owners = ScannerQueuedOwners::Indexed(owners);
+                }
+                ScannerQueuedOwners::Indexed(owners) => {
+                    owners.insert(
+                        sequence,
+                        QueuedOwner {
+                            request_id: request.id.clone(),
+                            observation_id,
+                        },
+                    );
+                }
+            }
+            entry.refcount += 1;
+        } else {
+            self.dedup_keys.insert(
+                key.clone(),
+                DedupKeyEntry {
+                    refcount: 1,
+                    representative_request_id: request.id.clone(),
+                    representative_sequence: sequence,
+                    representative_observation_id: observation_id,
+                    scanner_queued_owners: ScannerQueuedOwners::Single(sequence),
+                },
+            );
+        }
         let source = request.source;
         self.heap.push(PriorityQueueItem {
             priority: request.priority,
             sequence: self.sequence,
             dedup_key: key,
             request,
+            observation_id,
             replacement_targets_frozen: frozen,
         });
         if is_best_effort_source(source) {
@@ -371,7 +444,12 @@ impl PriorityHealQueue {
         self.can_displace_lower_priority_where(priority, |_| true)
     }
 
-    pub(super) fn push_displacing_lower_priority_where<F>(&mut self, request: HealRequest, can_displace: F) -> Option<HealRequest>
+    pub(super) fn push_displacing_lower_priority_where<F>(
+        &mut self,
+        request: HealRequest,
+        can_displace: F,
+        observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
+    ) -> Option<HealRequest>
     where
         F: Fn(&HealRequest) -> bool,
     {
@@ -402,7 +480,7 @@ impl PriorityHealQueue {
         self.heap = retained;
 
         let displaced = displaced.map(|item| {
-            Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item.dedup_key);
+            Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item);
             self.remove_best_effort_count(item.request.source);
             self.refresh_dedup_representative(&item.dedup_key);
             item.request
@@ -413,7 +491,7 @@ impl PriorityHealQueue {
             // into `debug_assert_eq!` — in release builds (`debug_assertions` off) the whole
             // macro, including its argument expression, is compiled out, which would silently
             // drop the new high-priority request after having already evicted a queued item.
-            let outcome = self.push(request);
+            let outcome = self.push_with_replacement_scope(request, false, observation_id);
             debug_assert_eq!(outcome, QueuePushOutcome::Accepted);
         }
 
@@ -422,7 +500,7 @@ impl PriorityHealQueue {
 
     #[cfg(test)]
     pub(super) fn push_displacing_lower_priority(&mut self, request: HealRequest) -> Option<HealRequest> {
-        self.push_displacing_lower_priority_where(request, |_| true)
+        self.push_displacing_lower_priority_where(request, |_| true, rustfs_heal_contracts::completion::new_heal_observation_id())
     }
 
     /// Get statistics about queue contents by priority
@@ -446,14 +524,10 @@ impl PriorityHealQueue {
 
     #[cfg(test)]
     pub(super) fn pop(&mut self) -> Option<HealRequest> {
-        self.heap.pop().map(|item| {
-            Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item.dedup_key);
-            self.remove_best_effort_count(item.request.source);
-            item.request
-        })
+        self.heap.pop().map(|item| self.remove_queued_item(item).request)
     }
 
-    pub(super) fn pop_runnable_with_skips<F, G>(&mut self, can_run: F, skip_label: G) -> (Option<HealRequest>, Vec<String>)
+    pub(super) fn pop_runnable_with_skips<F, G>(&mut self, can_run: F, skip_label: G) -> (Option<QueuedHeal>, Vec<String>)
     where
         F: Fn(&HealRequest) -> bool,
         G: Fn(&HealRequest) -> Option<String>,
@@ -475,17 +549,10 @@ impl PriorityHealQueue {
 
         self.restore_deferred_items(deferred);
 
-        (
-            selected.map(|item| {
-                Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item.dedup_key);
-                self.remove_best_effort_count(item.request.source);
-                item.request
-            }),
-            skipped,
-        )
+        (selected.map(|item| self.remove_queued_item(item)), skipped)
     }
 
-    pub(super) fn pop_runnable_with_fairness<F, G>(&mut self, can_run: F, skip_label: G) -> (Option<HealRequest>, Vec<String>)
+    pub(super) fn pop_runnable_with_fairness<F, G>(&mut self, can_run: F, skip_label: G) -> (Option<QueuedHeal>, Vec<String>)
     where
         F: Fn(&HealRequest) -> bool,
         G: Fn(&HealRequest) -> Option<String>,
@@ -554,15 +621,22 @@ impl PriorityHealQueue {
         self.heap = BinaryHeap::from(items);
 
         let chosen = chosen.map(|item| {
-            let request = item.request;
-            Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item.dedup_key);
-            self.remove_best_effort_count(request.source);
+            let request = self.remove_queued_item(item);
             self.record_dispatch(&request);
             request
         });
         (chosen, skipped)
     }
 
+    fn remove_queued_item(&mut self, item: PriorityQueueItem) -> QueuedHeal {
+        Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item);
+        self.remove_best_effort_count(item.request.source);
+        QueuedHeal {
+            request: item.request,
+            observation_id: item.observation_id,
+        }
+    }
+
     fn record_dispatch(&mut self, request: &HealRequest) {
         if is_best_effort_source(request.source) {
             self.mrf_normal_dispatches_since_best_effort = 0;
@@ -667,12 +741,34 @@ impl PriorityHealQueue {
         }
     }
 
-    pub(super) fn decrement_or_remove_dedup_key(dedup_keys: &mut HashMap<String, DedupKeyEntry>, key: &str) {
-        if let Some(entry) = dedup_keys.get_mut(key) {
+    fn decrement_or_remove_dedup_key(dedup_keys: &mut HashMap<String, DedupKeyEntry>, item: &PriorityQueueItem) {
+        if let Some(entry) = dedup_keys.get_mut(&item.dedup_key) {
+            match &mut entry.scanner_queued_owners {
+                ScannerQueuedOwners::Single(sequence) if entry.refcount != 1 || *sequence != item.sequence => {
+                    entry.scanner_queued_owners = ScannerQueuedOwners::Indexed(BTreeMap::new());
+                    entry.representative_observation_id = None;
+                }
+                ScannerQueuedOwners::Single(_) => {}
+                ScannerQueuedOwners::Indexed(owners) => {
+                    let matches_holder = owners.len() == entry.refcount
+                        && owners.get(&item.sequence).is_some_and(|owner| {
+                            owner.request_id == item.request.id && owner.observation_id == item.observation_id
+                        });
+                    if matches_holder {
+                        owners.remove(&item.sequence);
+                    } else {
+                        owners.clear();
+                        entry.representative_observation_id = None;
+                    }
+                }
+            }
             if entry.refcount <= 1 {
-                dedup_keys.remove(key);
+                dedup_keys.remove(&item.dedup_key);
             } else {
                 entry.refcount -= 1;
+                if entry.representative_sequence == item.sequence {
+                    entry.representative_observation_id = None;
+                }
             }
         }
     }
@@ -744,18 +840,59 @@ impl PriorityHealQueue {
     }
 
     pub(super) fn queued_request_id_for_dedup_key(&self, key: &str) -> Option<&str> {
-        self.dedup_keys.get(key).map(|entry| entry.representative_request_id.as_str())
+        self.queued_legacy_owner_for_dedup_key(key).map(|(id, _)| id)
     }
 
-    /// Re-elect the representative for `key` from the queue entries holding
-    /// it. Needed after a holder leaves the queue *without* becoming active
-    /// (canceled by id, or displaced): the former opener may be the request
-    /// that just left, and a merge receipt must never name an id that
-    /// resolves nowhere. The scheduler pop path does not need this — the
-    /// popped request surfaces in `active_heals` under the same id and the
-    /// duplicate pre-check consults active heals before the queue. No-op for
-    /// released keys; the survivor scan only runs when a key still has
-    /// holders, which under forced duplicates is the rare admin path.
+    pub(super) fn queued_legacy_owner_for_dedup_key(
+        &self,
+        key: &str,
+    ) -> Option<(&str, Option<rustfs_heal_contracts::completion::HealObservationId>)> {
+        let entry = self.dedup_keys.get(key)?;
+        Some((entry.representative_request_id.as_str(), entry.representative_observation_id))
+    }
+
+    pub(super) fn queued_scanner_owner_for_dedup_key(
+        &self,
+        key: &str,
+    ) -> Option<(&str, Option<rustfs_heal_contracts::completion::HealObservationId>)> {
+        let entry = self.dedup_keys.get(key)?;
+        match &entry.scanner_queued_owners {
+            ScannerQueuedOwners::Single(sequence) if entry.refcount == 1 && entry.representative_sequence == *sequence => {
+                Some((entry.representative_request_id.as_str(), entry.representative_observation_id))
+            }
+            ScannerQueuedOwners::Indexed(owners) if owners.len() == entry.refcount => owners
+                .first_key_value()
+                .map(|(_, owner)| (owner.request_id.as_str(), owner.observation_id)),
+            _ => None,
+        }
+    }
+
+    #[cfg(test)]
+    pub(super) fn scanner_queued_request_id_for_dedup_key(&self, key: &str) -> Option<&str> {
+        self.queued_scanner_owner_for_dedup_key(key).map(|(id, _)| id)
+    }
+
+    #[cfg(test)]
+    pub(super) fn queued_observation_for_dedup_key(
+        &self,
+        key: &str,
+    ) -> Option<rustfs_heal_contracts::completion::HealObservationId> {
+        self.queued_legacy_owner_for_dedup_key(key)
+            .and_then(|(_, observation_id)| observation_id)
+    }
+
+    #[cfg(test)]
+    pub(super) fn queued_observation_for_request_id(
+        &self,
+        id: &str,
+    ) -> Option<rustfs_heal_contracts::completion::HealObservationId> {
+        let mut matching = self.heap.iter().filter(|item| item.request.id == id);
+        let observation_id = matching.next()?.observation_id;
+        if matching.next().is_some() { None } else { observation_id }
+    }
+
+    /// Re-elect the legacy representative from the heap after cancellation or
+    /// displacement. Dequeue leaves it unchanged for existing callers.
     pub(super) fn refresh_dedup_representative(&mut self, key: &str) {
         if !self.dedup_keys.contains_key(key) {
             return;
@@ -764,10 +901,12 @@ impl PriorityHealQueue {
             .heap
             .iter()
             .find(|item| item.dedup_key == key)
-            .map(|item| item.request.id.clone())
+            .map(|item| (item.request.id.clone(), item.sequence, item.observation_id))
             && let Some(entry) = self.dedup_keys.get_mut(key)
         {
-            entry.representative_request_id = id;
+            entry.representative_request_id = id.0;
+            entry.representative_sequence = id.1;
+            entry.representative_observation_id = id.2;
         }
     }
 
@@ -786,7 +925,7 @@ impl PriorityHealQueue {
         while let Some(item) = self.heap.pop() {
             if removed.is_none() && item.request.id == request_id {
                 let key = item.dedup_key.clone();
-                Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &key);
+                Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item);
                 self.remove_best_effort_count(item.request.source);
                 affected_key = Some(key);
                 removed = Some(item.request);
@@ -812,7 +951,7 @@ impl PriorityHealQueue {
 
         while let Some(item) = self.heap.pop() {
             if should_remove(&item.request) {
-                Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item.dedup_key);
+                Self::decrement_or_remove_dedup_key(&mut self.dedup_keys, &item);
                 self.remove_best_effort_count(item.request.source);
                 affected_keys.push(item.dedup_key);
                 removed.push(item.request);

crates/heal/src/heal/manager/scheduler.rs

@@ -15,6 +15,27 @@ use super::disposition::record_task_disposition;
 /// The heal scheduler: queue consumption loop and its skip/metric helpers.
 use super::*;
 
+pub(super) fn current_task_observation_id(
+    active: &HashMap<String, Arc<HealTask>>,
+    task: &Arc<HealTask>,
+) -> Option<rustfs_heal_contracts::completion::HealObservationId> {
+    active
+        .get(&task.id)
+        .filter(|owner| Arc::ptr_eq(owner, task))
+        .and_then(|_| task.observation_id)
+}
+
+pub(super) fn current_retry_observation_id(
+    retrying: &HashMap<String, RetryingHeal>,
+    task_id: &str,
+    cancel_token: &CancellationToken,
+) -> Option<rustfs_heal_contracts::completion::HealObservationId> {
+    retrying
+        .get(task_id)
+        .filter(|owner| &owner.cancel_token == cancel_token)
+        .and_then(|owner| owner.observation_id)
+}
+
 pub(super) fn retry_admission_delay(
     grace_deadline: Option<u64>,
     ordinary_delay: Duration,
@@ -211,7 +232,9 @@ impl HealManager {
                 queue.pop_runnable_with_fairness(|_| true, |_| None).0
             };
 
-            if let Some(mut request) = selected_request {
+            if let Some(queued) = selected_request {
+                let observation_id = queued.observation_id;
+                let mut request = queued.request;
                 request.options.timeout.get_or_insert(config.task_timeout);
                 let task_priority = request.priority;
                 let task_type_label = heal_request_type_label(&request).to_string();
@@ -229,6 +252,7 @@ impl HealManager {
                 let mainline_pacer = running_mainline_pacer(&request, &config, workload_provider);
                 let task = Arc::new(
                     HealTask::from_replacement_recovery_request(request, storage.clone(), replacement_resume_endpoint)
+                        .with_observation_id(observation_id)
                         .with_mainline_pacer(mainline_pacer)
                         .with_admin_recovery(root_recovery.clone()),
                 );
@@ -336,6 +360,9 @@ impl HealManager {
                     tests::pause_completed_retention_before_publish(&task_id, &completed_status).await;
                     let mut active_heals_guard = active_heals_clone.lock().await;
                     let owns_completion = active_heals_guard.contains_key(&task_id);
+                    // The legacy scheduler checks only the ID; observation needs the
+                    // actual task object because IDs can be reused concurrently.
+                    let observation_id = current_task_observation_id(&active_heals_guard, &task);
                     let cancelled_snapshot = if owns_completion {
                         None
                     } else {
@@ -428,6 +455,7 @@ impl HealManager {
                                 request.id.clone(),
                                 RetryingHeal {
                                     request: request.clone(),
+                                    observation_id,
                                     error: error.clone(),
                                     cancel_token: cancel_token.clone(),
                                 },
@@ -446,6 +474,7 @@ impl HealManager {
                             &task_id,
                             completed_status_entry,
                             terminal_completion,
+                            observation_id,
                         )
                         .await;
                     }
@@ -593,8 +622,18 @@ impl HealManager {
                                 if retry_cancel_token.is_cancelled() || !retrying.contains_key(&retry_request_id) {
                                     return;
                                 }
-                                let admission_decision =
-                                    Self::admit_request_to_queue(&mut queue, retry_request.clone(), &retry_config, "retry", true);
+                                // A later retry can reuse the ID. Only the same
+                                // cancellation token proves this is its owner.
+                                let retry_observation_id =
+                                    current_retry_observation_id(&retrying, &retry_request_id, &retry_cancel_token);
+                                let admission_decision = Self::admit_request_to_queue(
+                                    &mut queue,
+                                    retry_request.clone(),
+                                    &retry_config,
+                                    "retry",
+                                    true,
+                                    retry_observation_id,
+                                );
                                 let admission = admission_decision.result;
                                 let should_notify = matches!(admission, HealAdmissionResult::Accepted)
                                     && retry_config.event_driven_scheduler_enable;

crates/heal/src/heal/manager/tests.rs

@@ -34,6 +34,7 @@ mod auto_scan;
 mod completion;
 mod disposition;
 mod legacy_ambiguity_logging;
+mod queued_representative;
 mod running_mainline;
 
 use super::super::{DiskOption, DiskStore, Endpoint, new_disk, storage_api::status::BucketInfo};
@@ -935,6 +936,7 @@ async fn heal_start_retry_scheduler_carries_explicit_budget_and_identity() {
 
 #[tokio::test]
 async fn heal_start_retry_scheduler_carries_explicit_budget_across_retries() {
+    let mut terminals = rustfs_heal_contracts::completion::subscribe_observed_heal_completions();
     let manager = HealManager::new_without_root_recovery_for_test(
         Arc::new(MockStorage),
         Some(HealConfig {
@@ -948,10 +950,11 @@ async fn heal_start_retry_scheduler_carries_explicit_budget_across_retries() {
     request.options.timeout = Some(Duration::from_secs(60));
     let task_id = request.id.clone();
     let created_at = request.created_at;
-    manager
-        .submit_heal_request(request)
+    let receipt = manager
+        .submit_heal_request_with_observation_and_alias(request, false)
         .await
         .expect("admit explicit-budget task");
+    let observation_id = receipt.observation_id.expect("accepted owner has an observation identity");
 
     let mut previous_remaining = Duration::from_secs(60);
     for expected_attempt in 1..=3 {
@@ -967,7 +970,9 @@ async fn heal_start_retry_scheduler_carries_explicit_budget_across_retries() {
         .await
         .expect("recoverable executor failure should enter retry backoff");
 
-        let retry = manager.retrying_heals.lock().await[&task_id].request.clone();
+        let retry_owner = manager.retrying_heals.lock().await[&task_id].clone();
+        assert_eq!(retry_owner.observation_id, Some(observation_id));
+        let retry = retry_owner.request;
         assert_eq!(retry.id, task_id);
         assert_eq!(retry.created_at, created_at);
         assert_eq!(retry.source, HealRequestSource::Admin);
@@ -993,6 +998,10 @@ async fn heal_start_retry_scheduler_carries_explicit_budget_across_retries() {
         .await
         .expect("retry backoff should requeue the same task id");
         assert_eq!(manager.operations_snapshot().await.queue_length, 1);
+        assert_eq!(
+            manager.heal_queue.lock().await.queued_observation_for_request_id(&task_id),
+            Some(observation_id)
+        );
     }
 
     process_manager_queue_once(&manager).await;
@@ -1013,6 +1022,17 @@ async fn heal_start_retry_scheduler_carries_explicit_budget_across_retries() {
     );
     assert_eq!(manager.operations_snapshot().await.queue_length, 0);
     assert_eq!(manager.operations_snapshot().await.retrying_tasks, 0);
+    let terminal = tokio::time::timeout(Duration::from_secs(5), async {
+        loop {
+            let terminal = terminals.recv().await.expect("terminal channel remains open");
+            if terminal.task_id == task_id {
+                break terminal;
+            }
+        }
+    })
+    .await
+    .expect("retry exhaustion emits one terminal");
+    assert_eq!(terminal.observation_id, Some(observation_id));
 }
 
 struct ManagerRecoveryTestHook {
@@ -1206,6 +1226,32 @@ fn test_push_displacing_lower_priority_actually_enqueues_new_request() {
     assert_eq!(queue.len(), 0);
 }
 
+#[test]
+fn queued_observation_tracks_the_holder_sequence_when_ids_repeat() {
+    let mut queue = PriorityHealQueue::new();
+    let first = bucket_request("same-owner-key", HealPriority::Normal, HealRequestSource::Internal);
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let mut second = first.clone();
+    second.force_start = true;
+    assert_eq!(queue.push_with_replacement_scope(first, false, Some(11)), QueuePushOutcome::Accepted);
+    assert_eq!(queue.push_with_replacement_scope(second, false, Some(12)), QueuePushOutcome::Accepted);
+    assert_eq!(queue.queued_observation_for_dedup_key(&key), Some(11));
+    assert_eq!(
+        queue.queued_observation_for_request_id(&queue.heap.peek().expect("holder").request.id),
+        None
+    );
+
+    let (first, _) = queue.pop_runnable_with_fairness(|_| true, |_| None);
+    assert_eq!(first.expect("first holder").observation_id, Some(11));
+    assert_eq!(
+        queue.queued_observation_for_dedup_key(&key),
+        None,
+        "a departed representative is unproven"
+    );
+    let (second, _) = queue.pop_runnable_with_fairness(|_| true, |_| None);
+    assert_eq!(second.expect("second holder").observation_id, Some(12));
+}
+
 #[test]
 fn queued_request_id_for_dedup_key_tracks_the_representative() {
     let mut queue = PriorityHealQueue::new();
@@ -1214,6 +1260,7 @@ fn queued_request_id_for_dedup_key_tracks_the_representative() {
     let first_id = first.id.clone();
     let first_key = PriorityHealQueue::make_dedup_key(&first);
     assert_eq!(queue.push(first), QueuePushOutcome::Accepted);
+    assert!(queue.queued_observation_for_dedup_key(&first_key).is_some());
 
     // A forced duplicate of the same target opens a second entry under
     // the same key; the representative stays the request that opened it.
@@ -1341,6 +1388,7 @@ async fn durable_mrf_anchor_snapshot_follows_live_owners_and_ignores_stale_notic
     manager.retrying_heals.lock().await.insert(
         "retry-merged-active".into(),
         RetryingHeal {
+            observation_id: None,
             request: retry_request,
             error: "retry pending".into(),
             cancel_token: CancellationToken::new(),
@@ -2590,6 +2638,7 @@ async fn automatic_replacement_frozen_targets_reject_late_disks_but_cover_duplic
                 manager.retrying_heals.lock().await.insert(
                     owner_id.clone(),
                     RetryingHeal {
+                        observation_id: None,
                         request: owner,
                         error: "target unavailable".to_string(),
                         cancel_token: CancellationToken::new(),
@@ -2601,7 +2650,7 @@ async fn automatic_replacement_frozen_targets_reject_late_disks_but_cover_duplic
                 let mut queue = manager.heal_queue.lock().await;
                 let context = if state == "grace" { "retry" } else { "auto_scan" };
                 assert_eq!(
-                    HealManager::admit_request_to_queue(&mut queue, owner, &config, context, true).result,
+                    HealManager::admit_request_to_queue(&mut queue, owner, &config, context, true, None).result,
                     HealAdmissionResult::Accepted
                 );
                 assert!(
@@ -2725,7 +2774,7 @@ fn automatic_replacement_direct_admission_checks_frozen_targets_before_capacity(
     let owner_id = owner.id.clone();
     assert_eq!(queue.push(owner), QueuePushOutcome::Accepted);
     let admit = |queue: &mut PriorityHealQueue, request, frozen| {
-        HealManager::admit_request_to_queue(queue, request, &config, "auto_scan", frozen).result
+        HealManager::admit_request_to_queue(queue, request, &config, "auto_scan", frozen, None).result
     };
     assert_eq!(
         admit(&mut queue, automatic_replacement_request(&["replacement-b"]), false),
@@ -3958,6 +4007,7 @@ async fn insert_retrying_request(manager: &HealManager, request: HealRequest) ->
     manager.retrying_heals.lock().await.insert(
         task_id.clone(),
         RetryingHeal {
+            observation_id: None,
             request: request.clone(),
             error: "Lock acquisition timeout".to_string(),
             cancel_token: cancel_token.clone(),
@@ -4510,6 +4560,7 @@ async fn test_operations_snapshot_counts_retry_backoff_as_owned_work() {
     manager.retrying_heals.lock().await.insert(
         task_id,
         RetryingHeal {
+            observation_id: None,
             request,
             error: "transient".to_string(),
             cancel_token: CancellationToken::new(),
@@ -4789,6 +4840,7 @@ async fn test_get_task_report_preserves_retrying_options() {
     manager.retrying_heals.lock().await.insert(
         task_id.clone(),
         RetryingHeal {
+            observation_id: None,
             request,
             error: "transient".to_string(),
             cancel_token: CancellationToken::new(),

crates/heal/src/heal/manager/tests/admin_overlap.rs

@@ -37,6 +37,7 @@ async fn install_owner(manager: &HealManager, request: HealRequest, state: Owner
             manager.retrying_heals.lock().await.insert(
                 id.clone(),
                 RetryingHeal {
+                    observation_id: None,
                     request,
                     error: "recoverable fixture error".to_string(),
                     cancel_token: CancellationToken::new(),
@@ -450,6 +451,177 @@ async fn admin_overlap_normal_start_cannot_enter_force_start_cancellation_window
     assert_eq!(manager.heal_queue.lock().await.len(), 1);
 }
 
+#[tokio::test]
+async fn admin_force_start_rechecks_request_id_after_cancelling_overlaps() {
+    for source in [HealRequestSource::Scanner, HealRequestSource::Internal] {
+        let manager = manager_with_policy(HealOverlapPolicy::Merge);
+        let previous_id = install_owner(&manager, admin_prefix_request("bucket", "scope/child/"), OwnerState::Active).await;
+        let aliases = manager.task_aliases.lock().await;
+        let mut replacement = admin_prefix_request("bucket", "scope/");
+        replacement.force_start = true;
+        let request_id = replacement.id.clone();
+        let mut forced = Box::pin(manager.submit_heal_request_with_receipt(replacement));
+
+        tokio::time::timeout(
+            Duration::from_secs(5),
+            std::future::poll_fn(|cx| {
+                assert!(
+                    std::pin::pin!(tokio::task::unconstrained(forced.as_mut()))
+                        .poll(cx)
+                        .is_pending()
+                );
+                if manager.active_heals.try_lock().is_ok() {
+                    Poll::Ready(())
+                } else {
+                    cx.waker().wake_by_ref();
+                    Poll::Pending
+                }
+            }),
+        )
+        .await
+        .expect("forceStart reaches cancellation with registry locks released");
+
+        let mut competing = HealRequest::object("other-bucket".to_string(), "object".to_string(), None);
+        competing.id = request_id.clone();
+        competing.source = source;
+        competing.options.recreate_missing = false;
+        let receipt = manager
+            .submit_heal_request_with_receipt(competing)
+            .await
+            .expect("non-admin admission during forceStart cancellation");
+        assert_eq!(receipt.result, HealAdmissionResult::Accepted);
+        assert_eq!(receipt.task_id, request_id);
+
+        drop(aliases);
+        let receipt = forced.await.expect("forceStart returns a conflict");
+        assert_eq!(receipt.result, HealAdmissionResult::Dropped(HealAdmissionDropReason::AlreadyRunning));
+        assert_eq!(receipt.task_id, request_id);
+        let queue = manager.heal_queue.lock().await;
+        let same_id: Vec<_> = queue.requests().filter(|request| request.id == request_id).collect();
+        assert_eq!(same_id.len(), 1, "conflicting requests must not share an id");
+        assert_eq!(same_id[0].source, source);
+        drop(queue);
+        assert!(
+            matches!(manager.get_task_status(&previous_id).await, Ok(HealTaskStatus::Cancelled)),
+            "overlapping admin cancellation precedes the conflict recheck"
+        );
+    }
+}
+
+#[tokio::test]
+async fn forced_id_conflict_preserves_scanner_queued_owner() {
+    for competing_source in [HealRequestSource::Scanner, HealRequestSource::Internal] {
+        let manager = manager_with_policy(HealOverlapPolicy::Merge);
+        let previous_id = install_owner(&manager, admin_object_request("object"), OwnerState::Active).await;
+        let mut queued_ids = Vec::new();
+        for source in [
+            HealRequestSource::Scanner,
+            HealRequestSource::Internal,
+            HealRequestSource::Scanner,
+        ] {
+            let mut request = HealRequest::object("bucket".to_string(), "object".to_string(), None);
+            request.source = source;
+            request.force_start = true;
+            let id = request.id.clone();
+            let receipt = manager
+                .submit_heal_request_with_receipt(request)
+                .await
+                .expect("queue forced work");
+            assert_eq!(receipt.result, HealAdmissionResult::Accepted);
+            assert_eq!(receipt.task_id, id);
+            queued_ids.push(id);
+        }
+
+        // The first holder leaves the queue, leaving two forced tasks queued.
+        let selected = {
+            let mut queue = manager.heal_queue.lock().await;
+            let (selected, skipped) = queue.pop_runnable_with_skips(|_| true, |_| None);
+            assert!(skipped.is_empty());
+            let selected = selected.expect("first queued task should run");
+            assert_eq!(selected.id, queued_ids[0]);
+            assert_eq!(queue.len(), 2);
+            selected
+        };
+        let QueuedHeal { request, observation_id } = selected;
+        let completed_task = HealTask::from_request(request, manager.storage.clone()).with_observation_id(observation_id);
+        let mut completed = CompletedHealStatus::snapshot(&completed_task, HealTaskStatus::Completed).await;
+        Arc::make_mut(completed.outcome.as_mut().expect("completed task outcome")).finish(None);
+        manager
+            .completed_heals
+            .lock()
+            .await
+            .insert(queued_ids[0].clone(), Arc::new(completed));
+
+        let aliases = manager.task_aliases.lock().await;
+        let mut replacement = admin_object_request("object");
+        replacement.force_start = true;
+        let competing_id = replacement.id.clone();
+        let mut forced = Box::pin(manager.submit_heal_request_with_receipt(replacement));
+        tokio::time::timeout(
+            Duration::from_secs(5),
+            std::future::poll_fn(|cx| {
+                assert!(
+                    std::pin::pin!(tokio::task::unconstrained(forced.as_mut()))
+                        .poll(cx)
+                        .is_pending()
+                );
+                if manager.active_heals.try_lock().is_ok() {
+                    Poll::Ready(())
+                } else {
+                    cx.waker().wake_by_ref();
+                    Poll::Pending
+                }
+            }),
+        )
+        .await
+        .expect("forceStart reaches cancellation with registry locks released");
+
+        let mut competing = HealRequest::object("bucket".to_string(), "object".to_string(), None);
+        competing.id = competing_id.clone();
+        competing.source = competing_source;
+        competing.force_start = true;
+        let receipt = manager
+            .submit_heal_request_with_receipt(competing)
+            .await
+            .expect("competing same-key forced work");
+        assert_eq!(receipt.result, HealAdmissionResult::Accepted);
+        assert_eq!(receipt.task_id, competing_id);
+
+        drop(aliases);
+        let receipt = forced.await.expect("forceStart returns an ID conflict");
+        assert_eq!(receipt.result, HealAdmissionResult::Dropped(HealAdmissionDropReason::AlreadyRunning));
+        assert_eq!(receipt.task_id, competing_id);
+        assert!(!manager.active_heals.lock().await.contains_key(&competing_id));
+        assert!(!manager.retrying_heals.lock().await.contains_key(&competing_id));
+        assert!(matches!(manager.get_task_status(&previous_id).await, Ok(HealTaskStatus::Cancelled)));
+        {
+            let queue = manager.heal_queue.lock().await;
+            let same_id: Vec<_> = queue.requests().filter(|request| request.id == competing_id).collect();
+            assert_eq!(same_id.len(), 1, "the competing ID must have one live owner");
+            assert_eq!(same_id[0].source, competing_source);
+            assert_eq!(queue.len(), 3);
+        }
+
+        let mut scanner = HealRequest::object("bucket".to_string(), "object".to_string(), None);
+        scanner.source = HealRequestSource::Scanner;
+        let receipt = manager
+            .submit_heal_request_with_receipt(scanner)
+            .await
+            .expect("scanner should merge into queued work");
+        assert_eq!(receipt.result, HealAdmissionResult::Merged);
+        assert_ne!(receipt.task_id, queued_ids[0], "the completed holder cannot own a queued receipt");
+        assert!(
+            manager
+                .heal_queue
+                .lock()
+                .await
+                .requests()
+                .any(|request| request.id == receipt.task_id),
+            "the canonical receipt must name a live queued task"
+        );
+    }
+}
+
 #[tokio::test]
 async fn admin_overlap_cancel_cannot_miss_a_queued_to_active_transition() {
     let manager = manager_with_policy(HealOverlapPolicy::Merge);

crates/heal/src/heal/manager/tests/completion.rs

@@ -1,6 +1,208 @@
 use super::*;
 use crate::heal::outcome::{HealObjectIdentity, HealObjectKind, HealObjectOutcome};
-use rustfs_heal_contracts::{completion::subscribe_heal_completions, heal_channel::HealScanMode};
+use rustfs_heal_contracts::{
+    completion::{subscribe_heal_completions, subscribe_observed_heal_completions},
+    heal_channel::HealScanMode,
+};
+
+#[test]
+fn observation_requires_the_current_task_or_retry_object() {
+    let request = bucket_request("observation-object-owner", HealPriority::Normal, HealRequestSource::Internal);
+    let id = request.id.clone();
+    let stale = Arc::new(HealTask::from_request(request.clone(), Arc::new(MockStorage)).with_observation_id(Some(301)));
+    let current = Arc::new(HealTask::from_request(request.clone(), Arc::new(MockStorage)).with_observation_id(Some(302)));
+    let active = HashMap::from([(id.clone(), Arc::clone(&current))]);
+    assert_eq!(current_task_observation_id(&active, &stale), None);
+    assert_eq!(current_task_observation_id(&active, &current), Some(302));
+
+    let current_token = CancellationToken::new();
+    let stale_token = CancellationToken::new();
+    let retrying = HashMap::from([(
+        id.clone(),
+        RetryingHeal {
+            request,
+            observation_id: Some(303),
+            error: "retrying".into(),
+            cancel_token: current_token.clone(),
+        },
+    )]);
+    assert_eq!(current_retry_observation_id(&retrying, &id, &stale_token), None);
+    assert_eq!(current_retry_observation_id(&retrying, &id, &current_token), Some(303));
+}
+
+#[tokio::test]
+async fn queued_same_id_replay_is_unknown_but_canonical_merge_retains_owner_identity() {
+    let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+    let request = bucket_request("queued-id-replay-observation", HealPriority::Normal, HealRequestSource::Internal);
+    let first = manager
+        .submit_heal_request_with_observation_and_alias(request.clone(), false)
+        .await
+        .expect("first owner");
+    assert!(first.observation_id.is_some());
+    let replay = manager
+        .submit_heal_request_with_observation_and_alias(request, false)
+        .await
+        .expect("same ID replay");
+    assert_eq!(replay.result, HealAdmissionResult::Accepted);
+    assert_eq!(replay.task_id, first.task_id);
+    assert_eq!(replay.observation_id, None);
+
+    let duplicate = bucket_request("queued-id-replay-observation", HealPriority::Normal, HealRequestSource::Scanner);
+    let merged = manager
+        .submit_heal_request_with_observation_and_alias(duplicate, false)
+        .await
+        .expect("canonical merge");
+    assert_eq!(merged.result, HealAdmissionResult::Merged);
+    assert_eq!(merged.task_id, first.task_id);
+    assert_eq!(merged.observation_id, first.observation_id);
+}
+
+#[tokio::test]
+async fn merged_receipt_uses_live_active_or_retrying_owner_identity() {
+    let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+    let request = bucket_request("owner-observation-states", HealPriority::Normal, HealRequestSource::Internal);
+    let id = request.id.clone();
+    manager.active_heals.lock().await.insert(
+        id.clone(),
+        Arc::new(HealTask::from_request(request.clone(), Arc::new(MockStorage)).with_observation_id(Some(201))),
+    );
+    let scanner = bucket_request("owner-observation-states", HealPriority::Normal, HealRequestSource::Scanner);
+    let active = manager
+        .submit_heal_request_with_observation_and_alias(scanner.clone(), false)
+        .await
+        .expect("active merge");
+    assert_eq!(active.result, HealAdmissionResult::Merged);
+    assert_eq!(active.task_id, id);
+    assert_eq!(active.observation_id, Some(201));
+    manager.active_heals.lock().await.remove(&id);
+    manager.retrying_heals.lock().await.insert(
+        id.clone(),
+        RetryingHeal {
+            request,
+            observation_id: Some(202),
+            error: "retrying".into(),
+            cancel_token: CancellationToken::new(),
+        },
+    );
+    let mut scanner_retry = scanner;
+    scanner_retry.id = Uuid::new_v4().to_string();
+    let retrying = manager
+        .submit_heal_request_with_observation_and_alias(scanner_retry, false)
+        .await
+        .expect("retry merge");
+    assert_eq!(retrying.result, HealAdmissionResult::Merged);
+    assert_eq!(retrying.task_id, id);
+    assert_eq!(retrying.observation_id, Some(202));
+}
+
+#[tokio::test]
+async fn cancelled_or_displaced_queue_owner_does_not_reuse_its_observation_identity() {
+    for displace in [false, true] {
+        let manager = HealManager::new_without_root_recovery_for_test(
+            Arc::new(MockStorage),
+            Some(HealConfig {
+                queue_size: 1,
+                event_driven_scheduler_enable: false,
+                ..Default::default()
+            }),
+        );
+        let request = bucket_request("removed-observation-owner", HealPriority::Low, HealRequestSource::Scanner);
+        let old = manager
+            .submit_heal_request_with_observation_and_alias(request.clone(), false)
+            .await
+            .expect("first owner");
+        assert_eq!(old.result, HealAdmissionResult::Accepted);
+        assert!(old.observation_id.is_some());
+        if displace {
+            let urgent = bucket_request("displacing-owner", HealPriority::Urgent, HealRequestSource::Internal);
+            let urgent_id = urgent.id.clone();
+            let admitted = manager
+                .submit_heal_request_with_observation_and_alias(urgent, false)
+                .await
+                .expect("displacing owner");
+            assert_eq!(admitted.result, HealAdmissionResult::Accepted);
+            assert!(
+                manager
+                    .heal_queue
+                    .lock()
+                    .await
+                    .requests()
+                    .all(|queued| queued.id != old.task_id)
+            );
+            manager.cancel_task(&urgent_id).await.expect("free queue after displacement");
+        } else {
+            manager.cancel_task(&old.task_id).await.expect("cancel queued owner");
+        }
+        let next = manager
+            .submit_heal_request_with_observation_and_alias(request, false)
+            .await
+            .expect("readmit same id");
+        assert_eq!(next.result, HealAdmissionResult::Accepted);
+        assert_eq!(next.task_id, old.task_id);
+        assert!(next.observation_id.is_some());
+        assert_ne!(next.observation_id, old.observation_id);
+    }
+}
+
+#[tokio::test]
+async fn reused_id_has_distinct_owner_generations_in_receipts_and_terminals() {
+    let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+    let mut receiver = subscribe_observed_heal_completions();
+    let request = bucket_request("observation-id-reuse", HealPriority::Normal, HealRequestSource::Internal);
+
+    let first = manager
+        .submit_heal_request_with_observation_and_alias(request.clone(), false)
+        .await
+        .expect("first owner");
+    let mut scanner = bucket_request("observation-id-reuse", HealPriority::Normal, HealRequestSource::Scanner);
+    let merged = manager
+        .submit_heal_request_with_observation_and_alias(scanner.clone(), false)
+        .await
+        .expect("first merge");
+    assert_eq!(merged.result, HealAdmissionResult::Merged);
+    assert_eq!(merged.task_id, first.task_id);
+    assert!(first.observation_id.is_some());
+    assert_eq!(merged.observation_id, first.observation_id);
+    process_manager_queue_once(&manager).await;
+    let first_terminal = tokio::time::timeout(Duration::from_secs(5), async {
+        loop {
+            let terminal = receiver.recv().await.expect("terminal channel");
+            if terminal.task_id == first.task_id {
+                break terminal;
+            }
+        }
+    })
+    .await
+    .expect("first terminal");
+    assert_eq!(first_terminal.observation_id, first.observation_id);
+
+    let second = manager
+        .submit_heal_request_with_observation_and_alias(request, false)
+        .await
+        .expect("reused id");
+    assert_eq!(second.result, HealAdmissionResult::Accepted);
+    assert_eq!(second.task_id, first.task_id);
+    assert_ne!(second.observation_id, first.observation_id);
+    scanner.id = Uuid::new_v4().to_string();
+    let merged_again = manager
+        .submit_heal_request_with_observation_and_alias(scanner, false)
+        .await
+        .expect("second merge");
+    assert_eq!(merged_again.result, HealAdmissionResult::Merged);
+    assert_eq!(merged_again.observation_id, second.observation_id);
+    process_manager_queue_once(&manager).await;
+    let second_terminal = tokio::time::timeout(Duration::from_secs(5), async {
+        loop {
+            let terminal = receiver.recv().await.expect("terminal channel");
+            if terminal.task_id == second.task_id && terminal.observation_id == second.observation_id {
+                break terminal;
+            }
+        }
+    })
+    .await
+    .expect("second terminal");
+    assert_eq!(second_terminal.observation_id, second.observation_id);
+}
 
 #[tokio::test]
 async fn canonical_completion_publishes_typed_objects_only_for_terminal_untruncated_results() {
@@ -43,12 +245,12 @@ async fn canonical_completion_publishes_typed_objects_only_for_terminal_untrunca
         error: "retry".into(),
         retry_attempt: 1,
     };
-    publish_completed_heal(&completed_heals, &aliases, &id, completed.clone(), false).await;
+    publish_completed_heal(&completed_heals, &aliases, &id, completed.clone(), false, Some(1)).await;
     while let Ok(observed) = receiver.try_recv() {
         assert_ne!(observed.task_id, id, "a retry attempt must not publish a terminal");
     }
     completed.status = HealTaskStatus::Completed;
-    publish_completed_heal(&completed_heals, &aliases, &id, completed.clone(), true).await;
+    publish_completed_heal(&completed_heals, &aliases, &id, completed.clone(), true, Some(1)).await;
     let observed = tokio::time::timeout(Duration::from_secs(1), async {
         loop {
             let event = receiver.recv().await.expect("terminal broadcaster stays open");
@@ -73,7 +275,7 @@ async fn canonical_completion_publishes_typed_objects_only_for_terminal_untrunca
     outcome.objects_truncated = true;
     completed.outcome = Some(Arc::new(outcome));
     let truncated_id = Uuid::new_v4().to_string();
-    publish_completed_heal(&completed_heals, &aliases, &truncated_id, completed, true).await;
+    publish_completed_heal(&completed_heals, &aliases, &truncated_id, completed, true, Some(1)).await;
     let truncated = tokio::time::timeout(Duration::from_secs(1), async {
         loop {
             let event = receiver.recv().await.expect("terminal broadcaster stays open");

crates/heal/src/heal/manager/tests/queued_representative.rs

@@ -0,0 +1,653 @@
+// Copyright 2026 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::*;
+
+fn object_request(source: HealRequestSource, priority: HealPriority, force_start: bool) -> HealRequest {
+    let mut request = HealRequest::new(
+        HealType::Object {
+            bucket: "canonical-owner".to_owned(),
+            object: "object".to_owned(),
+            version_id: None,
+        },
+        HealOptions::default(),
+        priority,
+    );
+    request.source = source;
+    request.force_start = force_start;
+    request
+}
+
+fn scoped_object_request(
+    source: HealRequestSource,
+    version_id: &str,
+    pool_index: Option<usize>,
+    set_index: Option<usize>,
+    force_start: bool,
+) -> HealRequest {
+    let mut request = object_request(source, HealPriority::Low, force_start);
+    let HealType::Object { version_id: version, .. } = &mut request.heal_type else {
+        unreachable!("object_request always constructs an object heal")
+    };
+    *version = Some(version_id.to_owned());
+    request.options.pool_index = pool_index;
+    request.options.set_index = set_index;
+    request.options.recreate_missing = source != HealRequestSource::Scanner;
+    request
+}
+
+#[tokio::test]
+async fn scanner_receipt_tracks_scoped_read_repair_forced_holders() {
+    let manager = HealManager::new_without_root_recovery_for_test(
+        Arc::new(MockStorage),
+        Some(HealConfig {
+            queue_size: 16,
+            low_priority_merge_enable: true,
+            ..HealConfig::default()
+        }),
+    );
+    let version = "00000000-0000-4000-8000-000000000001";
+    let original = scoped_object_request(HealRequestSource::ReadRepair, version, Some(0), Some(1), false);
+    let original_id = original.id.clone();
+    let key = PriorityHealQueue::make_dedup_key(&original);
+    let admitted = manager
+        .submit_heal_request_with_receipt(original)
+        .await
+        .expect("admit read-repair owner");
+    assert_eq!(admitted.result, HealAdmissionResult::Accepted);
+    assert_eq!(admitted.task_id, original_id);
+
+    let receipt = manager
+        .submit_heal_request_with_receipt(scoped_object_request(HealRequestSource::Scanner, version, Some(0), Some(1), false))
+        .await
+        .expect("scanner merges into the scoped read-repair owner");
+    assert_eq!(receipt.result, HealAdmissionResult::Merged);
+    assert_eq!(receipt.task_id, original_id);
+
+    let first_forced = scoped_object_request(HealRequestSource::Internal, version, Some(0), Some(1), true);
+    let first_forced_id = first_forced.id.clone();
+    let second_forced = scoped_object_request(HealRequestSource::Internal, version, Some(0), Some(1), true);
+    let second_forced_id = second_forced.id.clone();
+    {
+        let mut queue = manager.heal_queue.lock().await;
+        assert_eq!(queue.push(first_forced), QueuePushOutcome::Accepted);
+        assert_eq!(queue.push(second_forced), QueuePushOutcome::Accepted);
+        let (selected, skipped) = queue.pop_runnable_with_skips(|_| true, |_| None);
+        assert!(skipped.is_empty());
+        assert_eq!(selected.expect("read-repair owner should leave first").id, original_id);
+        assert_eq!(queue.queued_request_id_for_dedup_key(&key), Some(original_id.as_str()));
+    }
+
+    let receipt = manager
+        .submit_heal_request_with_receipt(scoped_object_request(HealRequestSource::Scanner, version, Some(0), Some(1), false))
+        .await
+        .expect("scanner merges into the remaining owner");
+    assert_eq!(receipt.result, HealAdmissionResult::Merged);
+    assert_eq!(receipt.task_id, first_forced_id);
+
+    {
+        let mut queue = manager.heal_queue.lock().await;
+        let (selected, _) = queue.pop_runnable_with_skips(|request| request.id == first_forced_id, |_| None);
+        assert_eq!(selected.expect("first forced holder should leave").id, first_forced_id);
+        assert!(queue.contains_request_id(&second_forced_id));
+    }
+    let receipt = manager
+        .submit_heal_request_with_receipt(scoped_object_request(HealRequestSource::Scanner, version, Some(0), Some(1), false))
+        .await
+        .expect("scanner merges into the last queued holder");
+    assert_eq!(receipt.result, HealAdmissionResult::Merged);
+    assert_eq!(receipt.task_id, second_forced_id);
+}
+
+#[tokio::test]
+async fn scanner_receipt_does_not_merge_read_repair_with_a_different_scope_or_version() {
+    let version = "00000000-0000-4000-8000-000000000001";
+    let other_version = "00000000-0000-4000-8000-000000000002";
+    for (candidate_version, pool, set) in [
+        (version, None, None),
+        (version, Some(1), Some(1)),
+        (version, Some(0), Some(2)),
+        (other_version, Some(0), Some(1)),
+    ] {
+        let manager = HealManager::new_without_root_recovery_for_test(
+            Arc::new(MockStorage),
+            Some(HealConfig {
+                queue_size: 16,
+                low_priority_merge_enable: true,
+                ..HealConfig::default()
+            }),
+        );
+        let original = scoped_object_request(HealRequestSource::ReadRepair, version, Some(0), Some(1), false);
+        let original_id = original.id.clone();
+        let initial = manager
+            .submit_heal_request_with_receipt(original)
+            .await
+            .expect("admit read-repair owner");
+        assert_eq!(initial.result, HealAdmissionResult::Accepted);
+        assert_eq!(initial.task_id, original_id);
+
+        let candidate = scoped_object_request(HealRequestSource::Scanner, candidate_version, pool, set, false);
+        let candidate_id = candidate.id.clone();
+        let receipt = manager
+            .submit_heal_request_with_receipt(candidate)
+            .await
+            .expect("admit scanner with a distinct scope or version");
+        assert_eq!(
+            receipt.result,
+            HealAdmissionResult::Accepted,
+            "version={candidate_version}, pool={pool:?}, set={set:?}"
+        );
+        assert_eq!(receipt.task_id, candidate_id);
+        let queue = manager.heal_queue.lock().await;
+        assert!(queue.contains_request_id(&original_id));
+        assert!(queue.contains_request_id(&candidate_id));
+    }
+}
+
+async fn scanner_receipt_tracks_queued_owner(use_fairness: bool) {
+    let manager = HealManager::new_without_root_recovery_for_test(
+        Arc::new(MockStorage),
+        Some(HealConfig {
+            queue_size: 16,
+            low_priority_merge_enable: true,
+            overlap_policy: HealOverlapPolicy::Merge,
+            ..HealConfig::default()
+        }),
+    );
+
+    if use_fairness {
+        let mut queue = manager.heal_queue.lock().await;
+        for index in 0..4 {
+            let request = bucket_request(&format!("internal-{index}"), HealPriority::Normal, HealRequestSource::Internal);
+            assert_eq!(queue.push(request), QueuePushOutcome::Accepted);
+        }
+        for _ in 0..4 {
+            let (request, _) = queue.pop_runnable_with_fairness(|_| true, |_| None);
+            assert_eq!(request.expect("internal work should run").source, HealRequestSource::Internal);
+        }
+    }
+
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let first_id = first.id.clone();
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let second = object_request(HealRequestSource::Admin, HealPriority::High, true);
+    let second_id = second.id.clone();
+    for request in [first, second] {
+        assert_eq!(
+            manager
+                .submit_heal_request_with_receipt(request)
+                .await
+                .expect("admit task")
+                .result,
+            HealAdmissionResult::Accepted
+        );
+    }
+
+    let first = {
+        let mut queue = manager.heal_queue.lock().await;
+        let (selected, skipped) = if use_fairness {
+            queue.pop_runnable_with_fairness(|_| true, |_| None)
+        } else {
+            queue.pop_runnable_with_skips(|_| true, |_| None)
+        };
+        assert!(skipped.is_empty());
+        let selected = selected.expect("the first same-priority task should run");
+        assert_eq!(selected.id, first_id);
+        assert!(queue.contains_request_id(&second_id));
+        assert_eq!(
+            queue.queued_request_id_for_dedup_key(&key),
+            Some(first_id.as_str()),
+            "the existing representative for other sources must remain unchanged"
+        );
+        selected
+    };
+    let QueuedHeal { request, observation_id } = first;
+    manager.active_heals.lock().await.insert(
+        first_id.clone(),
+        Arc::new(HealTask::from_request(request, Arc::new(MockStorage)).with_observation_id(observation_id)),
+    );
+
+    let active = manager
+        .submit_heal_request_with_receipt(object_request(HealRequestSource::Scanner, HealPriority::Low, false))
+        .await
+        .expect("scanner admission while the first task is active");
+    assert_eq!(active.result, HealAdmissionResult::Merged);
+    assert_eq!(active.task_id, first_id, "active ownership keeps precedence");
+
+    let completed_task = manager
+        .active_heals
+        .lock()
+        .await
+        .remove(&first_id)
+        .expect("first task should leave active ownership");
+    let mut retained = CompletedHealStatus::snapshot(&completed_task, HealTaskStatus::Completed).await;
+    Arc::make_mut(retained.outcome.as_mut().expect("retained task outcome")).finish(None);
+    manager
+        .completed_heals
+        .lock()
+        .await
+        .insert(first_id.clone(), Arc::new(retained));
+    let queued = manager
+        .submit_heal_request_with_receipt(object_request(HealRequestSource::Scanner, HealPriority::Low, false))
+        .await
+        .expect("scanner admission after the first task leaves active state");
+    assert_eq!(queued.result, HealAdmissionResult::Merged);
+    assert_eq!(queued.task_id, second_id, "the receipt must name the remaining queued task");
+}
+
+#[tokio::test]
+async fn scanner_receipt_tracks_queued_owner_after_normal_dequeue() {
+    scanner_receipt_tracks_queued_owner(false).await;
+}
+
+#[tokio::test]
+async fn scanner_receipt_tracks_queued_owner_after_fair_dequeue() {
+    scanner_receipt_tracks_queued_owner(true).await;
+}
+
+#[tokio::test]
+async fn scanner_receipt_keeps_queued_owner_when_a_different_forced_task_runs() {
+    let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+    let first = object_request(HealRequestSource::Scanner, HealPriority::Low, false);
+    let first_id = first.id.clone();
+    let second = object_request(HealRequestSource::Admin, HealPriority::High, true);
+    let second_id = second.id.clone();
+    {
+        let mut queue = manager.heal_queue.lock().await;
+        assert_eq!(queue.push(first), QueuePushOutcome::Accepted);
+        assert_eq!(queue.push(second), QueuePushOutcome::Accepted);
+        let (selected, _) = queue.pop_runnable_with_skips(|_| true, |_| None);
+        assert_eq!(selected.expect("higher-priority forced task should run").id, second_id);
+    }
+    let receipt = manager
+        .submit_heal_request_with_receipt(object_request(HealRequestSource::Scanner, HealPriority::High, false))
+        .await
+        .expect("scanner admission after a non-representative task leaves the queue");
+    assert_eq!(receipt.result, HealAdmissionResult::Merged);
+    assert_eq!(receipt.task_id, first_id);
+}
+
+#[tokio::test]
+async fn scanner_receipt_reselects_after_the_queued_owner_is_cancelled() {
+    let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let first_id = first.id.clone();
+    let second = object_request(HealRequestSource::Admin, HealPriority::High, true);
+    let second_id = second.id.clone();
+    let third = object_request(HealRequestSource::Internal, HealPriority::High, true);
+    let third_id = third.id.clone();
+    {
+        let mut queue = manager.heal_queue.lock().await;
+        for request in [first, second, third] {
+            assert_eq!(queue.push(request), QueuePushOutcome::Accepted);
+        }
+        let (selected, _) = queue.pop_runnable_with_skips(|_| true, |_| None);
+        assert_eq!(selected.expect("first task should run").id, first_id);
+    }
+    let first_receipt = manager
+        .submit_heal_request_with_receipt(object_request(HealRequestSource::Scanner, HealPriority::High, false))
+        .await
+        .expect("first scanner admission");
+    assert_eq!(first_receipt.result, HealAdmissionResult::Merged);
+    assert!(first_receipt.task_id == second_id || first_receipt.task_id == third_id);
+    let remaining = if first_receipt.task_id == second_id {
+        third_id
+    } else {
+        second_id
+    };
+    manager.heal_queue.lock().await.remove_request_id(&first_receipt.task_id);
+
+    let next_receipt = manager
+        .submit_heal_request_with_receipt(object_request(HealRequestSource::Scanner, HealPriority::High, false))
+        .await
+        .expect("scanner admission after the queued owner is removed");
+    assert_eq!(next_receipt.result, HealAdmissionResult::Merged);
+    assert_eq!(next_receipt.task_id, remaining);
+}
+
+#[tokio::test]
+async fn scanner_receipt_reselects_after_multiple_forced_dequeues() {
+    let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let first_id = first.id.clone();
+    let second = object_request(HealRequestSource::Admin, HealPriority::High, true);
+    let second_id = second.id.clone();
+    let third = object_request(HealRequestSource::Internal, HealPriority::High, true);
+    let third_id = third.id.clone();
+    {
+        let mut queue = manager.heal_queue.lock().await;
+        for request in [first, second, third] {
+            assert_eq!(queue.push(request), QueuePushOutcome::Accepted);
+        }
+        let (selected, _) = queue.pop_runnable_with_skips(|_| true, |_| None);
+        assert_eq!(selected.expect("first task should run").id, first_id);
+    }
+    let first_receipt = manager
+        .submit_heal_request_with_receipt(object_request(HealRequestSource::Scanner, HealPriority::High, false))
+        .await
+        .expect("first scanner admission");
+    assert_eq!(first_receipt.result, HealAdmissionResult::Merged);
+    assert!(first_receipt.task_id == second_id || first_receipt.task_id == third_id);
+    let remaining = if first_receipt.task_id == second_id {
+        third_id
+    } else {
+        second_id
+    };
+    {
+        let mut queue = manager.heal_queue.lock().await;
+        let (selected, _) = queue.pop_runnable_with_skips(|request| request.id == first_receipt.task_id, |_| None);
+        assert_eq!(selected.expect("selected queued owner should run").id, first_receipt.task_id);
+    }
+    let next_receipt = manager
+        .submit_heal_request_with_receipt(object_request(HealRequestSource::Scanner, HealPriority::High, false))
+        .await
+        .expect("scanner admission after another queued owner starts");
+    assert_eq!(next_receipt.result, HealAdmissionResult::Merged);
+    assert_eq!(next_receipt.task_id, remaining);
+}
+
+#[test]
+fn scanner_owner_index_survives_a_single_remaining_holder_and_new_forced_work() {
+    let mut queue = PriorityHealQueue::new();
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let first_id = first.id.clone();
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let second = object_request(HealRequestSource::Admin, HealPriority::High, true);
+    let second_id = second.id.clone();
+    let third = object_request(HealRequestSource::Internal, HealPriority::High, true);
+    let third_id = third.id.clone();
+
+    assert_eq!(queue.push(first), QueuePushOutcome::Accepted);
+    assert!(matches!(&queue.dedup_keys[&key].scanner_queued_owners, ScannerQueuedOwners::Single(_)));
+    assert_eq!(queue.push(second), QueuePushOutcome::Accepted);
+    assert_eq!(queue.pop().expect("first queued task").id, first_id);
+    assert_eq!(queue.queued_request_id_for_dedup_key(&key), Some(first_id.as_str()));
+    assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(second_id.as_str()));
+
+    assert_eq!(queue.push(third), QueuePushOutcome::Accepted);
+    assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(second_id.as_str()));
+    assert_eq!(queue.pop().expect("second queued task").id, second_id);
+    assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(third_id.as_str()));
+}
+
+#[test]
+fn scanner_owner_index_distinguishes_holders_with_the_same_request_id() {
+    let mut queue = PriorityHealQueue::new();
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let shared_id = first.id.clone();
+    let mut second = object_request(HealRequestSource::Admin, HealPriority::High, true);
+    second.id.clone_from(&shared_id);
+    let third = object_request(HealRequestSource::Internal, HealPriority::High, true);
+    let third_id = third.id.clone();
+    for request in [first, second, third] {
+        assert_eq!(queue.push(request), QueuePushOutcome::Accepted);
+    }
+
+    assert_eq!(queue.pop().expect("first holder").id, shared_id);
+    assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(shared_id.as_str()));
+    assert_eq!(queue.remove_request_id(&shared_id).expect("second holder").id, shared_id);
+    assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(third_id.as_str()));
+    assert_eq!(queue.queued_request_id_for_dedup_key(&key), Some(third_id.as_str()));
+}
+
+#[test]
+fn scanner_owner_index_tracks_bulk_removal_and_key_release() {
+    let mut queue = PriorityHealQueue::new();
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let first_id = first.id.clone();
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let second = object_request(HealRequestSource::Admin, HealPriority::Normal, true);
+    let second_id = second.id.clone();
+    let third = object_request(HealRequestSource::Internal, HealPriority::Low, true);
+    let third_id = third.id.clone();
+    for request in [first, second, third] {
+        assert_eq!(queue.push(request), QueuePushOutcome::Accepted);
+    }
+
+    let removed = queue.remove_matching(|request| request.id == first_id || request.id == second_id);
+    assert_eq!(removed.len(), 2);
+    assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(third_id.as_str()));
+    assert_eq!(queue.queued_request_id_for_dedup_key(&key), Some(third_id.as_str()));
+    assert_eq!(queue.remove_matching(|request| request.id == third_id).len(), 1);
+    assert!(!queue.dedup_keys.contains_key(&key));
+
+    let next = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let next_id = next.id.clone();
+    assert_eq!(queue.push(next), QueuePushOutcome::Accepted);
+    assert!(matches!(&queue.dedup_keys[&key].scanner_queued_owners, ScannerQueuedOwners::Single(_)));
+    assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(next_id.as_str()));
+}
+
+#[test]
+fn scanner_owner_index_tracks_displacement_without_changing_legacy_reselection() {
+    let mut queue = PriorityHealQueue::new();
+    let first = object_request(HealRequestSource::Scanner, HealPriority::Low, false);
+    let first_id = first.id.clone();
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let second = object_request(HealRequestSource::Admin, HealPriority::Normal, true);
+    let second_id = second.id.clone();
+    assert_eq!(queue.push(first), QueuePushOutcome::Accepted);
+    assert_eq!(queue.push(second), QueuePushOutcome::Accepted);
+
+    let incoming = bucket_request("displacement", HealPriority::Urgent, HealRequestSource::Internal);
+    let displaced = queue
+        .push_displacing_lower_priority(incoming)
+        .expect("lower priority task should be displaced");
+    assert_eq!(displaced.id, first_id);
+    assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(second_id.as_str()));
+    assert_eq!(queue.queued_request_id_for_dedup_key(&key), Some(second_id.as_str()));
+}
+
+#[tokio::test]
+async fn scanner_receipt_rejects_a_missing_or_empty_holder_index() {
+    for missing in [true, false] {
+        let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+        let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+        let key = PriorityHealQueue::make_dedup_key(&first);
+        let second = object_request(HealRequestSource::Admin, HealPriority::High, true);
+        {
+            let mut queue = manager.heal_queue.lock().await;
+            assert_eq!(queue.push(first), QueuePushOutcome::Accepted);
+            assert_eq!(queue.push(second), QueuePushOutcome::Accepted);
+            let entry = queue.dedup_keys.get_mut(&key).expect("dedup key should exist");
+            entry.scanner_queued_owners = if missing {
+                ScannerQueuedOwners::Single(0)
+            } else {
+                ScannerQueuedOwners::Indexed(std::collections::BTreeMap::new())
+            };
+        }
+
+        for leave_one in [false, true] {
+            if leave_one {
+                manager.heal_queue.lock().await.pop().expect("one holder should leave");
+            }
+            let request = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+            let request_id = request.id.clone();
+            let receipt = manager
+                .submit_heal_request_with_receipt(request)
+                .await
+                .expect("admission should fail closed");
+            assert_eq!(receipt.result, HealAdmissionResult::Dropped(HealAdmissionDropReason::AlreadyRunning));
+            assert_eq!(receipt.task_id, request_id);
+        }
+    }
+}
+
+#[test]
+fn scanner_and_legacy_owners_keep_their_distinct_reselection_orders() {
+    let mut queue = PriorityHealQueue::new();
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let first_id = first.id.clone();
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let second = object_request(HealRequestSource::Admin, HealPriority::Low, true);
+    let second_id = second.id.clone();
+    let third = object_request(HealRequestSource::Internal, HealPriority::Normal, true);
+    let third_id = third.id.clone();
+    for request in [first, second, third] {
+        assert_eq!(queue.push(request), QueuePushOutcome::Accepted);
+    }
+
+    assert_eq!(queue.remove_request_id(&first_id).expect("first holder should be removed").id, first_id);
+    assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(second_id.as_str()));
+    assert_eq!(queue.queued_request_id_for_dedup_key(&key), Some(third_id.as_str()));
+}
+
+#[test]
+fn scanner_owner_index_tracks_a_series_of_forced_holders() {
+    let mut queue = PriorityHealQueue::new();
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let mut ids = vec![first.id.clone()];
+    assert_eq!(queue.push(first), QueuePushOutcome::Accepted);
+    for _ in 0..128 {
+        let request = object_request(HealRequestSource::Internal, HealPriority::High, true);
+        ids.push(request.id.clone());
+        assert_eq!(queue.push(request), QueuePushOutcome::Accepted);
+    }
+    for id in &ids {
+        assert_eq!(queue.scanner_queued_request_id_for_dedup_key(&key), Some(id.as_str()));
+        assert_eq!(&queue.pop().expect("indexed holder should remain queued").id, id);
+    }
+    assert!(!queue.dedup_keys.contains_key(&key));
+}
+
+#[tokio::test]
+async fn observed_scanner_and_legacy_receipts_pair_their_own_reselected_holders() {
+    let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let first_id = first.id.clone();
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let second = object_request(HealRequestSource::Internal, HealPriority::Low, true);
+    let second_id = second.id.clone();
+    let third = object_request(HealRequestSource::Internal, HealPriority::Normal, true);
+    let third_id = third.id.clone();
+    {
+        let mut queue = manager.heal_queue.lock().await;
+        for (request, observation_id) in [(first, 11), (second, 12), (third, 13)] {
+            assert_eq!(
+                queue.push_with_replacement_scope(request, false, Some(observation_id)),
+                QueuePushOutcome::Accepted
+            );
+        }
+        assert_eq!(queue.remove_request_id(&first_id).expect("remove first holder").id, first_id);
+        assert_eq!(queue.queued_scanner_owner_for_dedup_key(&key), Some((second_id.as_str(), Some(12))));
+        assert_eq!(queue.queued_legacy_owner_for_dedup_key(&key), Some((third_id.as_str(), Some(13))));
+    }
+
+    for (source, expected_id, expected_observation) in [
+        (HealRequestSource::Scanner, &second_id, 12),
+        (HealRequestSource::Internal, &third_id, 13),
+    ] {
+        let receipt = manager
+            .submit_heal_request_with_observation_and_alias(object_request(source, HealPriority::High, false), false)
+            .await
+            .expect("merge into queued owner");
+        assert_eq!(receipt.result, HealAdmissionResult::Merged);
+        assert_eq!(&receipt.task_id, expected_id);
+        assert_eq!(receipt.observation_id, Some(expected_observation));
+    }
+}
+
+#[tokio::test]
+async fn observed_same_id_holders_use_the_selected_sequence_not_the_id() {
+    let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let id = first.id.clone();
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let mut second = object_request(HealRequestSource::Internal, HealPriority::High, true);
+    second.id.clone_from(&id);
+    {
+        let mut queue = manager.heal_queue.lock().await;
+        assert_eq!(queue.push_with_replacement_scope(first, false, Some(21)), QueuePushOutcome::Accepted);
+        assert_eq!(queue.push_with_replacement_scope(second, false, Some(22)), QueuePushOutcome::Accepted);
+        let (selected, _) = queue.pop_runnable_with_skips(|_| true, |_| None);
+        let selected = selected.expect("first holder should run");
+        assert_eq!(selected.id, id);
+        assert_eq!(selected.observation_id, Some(21));
+        assert_eq!(queue.queued_scanner_owner_for_dedup_key(&key), Some((id.as_str(), Some(22))));
+        assert_eq!(queue.queued_legacy_owner_for_dedup_key(&key), Some((id.as_str(), None)));
+    }
+
+    for (source, expected_observation) in [(HealRequestSource::Scanner, Some(22)), (HealRequestSource::Internal, None)] {
+        let receipt = manager
+            .submit_heal_request_with_observation_and_alias(object_request(source, HealPriority::High, false), false)
+            .await
+            .expect("merge into the selected holder");
+        assert_eq!(receipt.result, HealAdmissionResult::Merged);
+        assert_eq!(receipt.task_id, id);
+        assert_eq!(receipt.observation_id, expected_observation);
+    }
+}
+
+#[test]
+fn displaced_holder_reselects_the_remaining_id_and_observation_together() {
+    let mut queue = PriorityHealQueue::new();
+    let first = object_request(HealRequestSource::Scanner, HealPriority::Low, false);
+    let first_id = first.id.clone();
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let second = object_request(HealRequestSource::Internal, HealPriority::Normal, true);
+    let second_id = second.id.clone();
+    assert_eq!(queue.push_with_replacement_scope(first, false, Some(31)), QueuePushOutcome::Accepted);
+    assert_eq!(queue.push_with_replacement_scope(second, false, Some(32)), QueuePushOutcome::Accepted);
+    let incoming = bucket_request("observation-displacement", HealPriority::Urgent, HealRequestSource::Internal);
+    let displaced = queue
+        .push_displacing_lower_priority_where(incoming, |_| true, Some(33))
+        .expect("lower-priority holder should be displaced");
+    assert_eq!(displaced.id, first_id);
+    assert_eq!(queue.queued_scanner_owner_for_dedup_key(&key), Some((second_id.as_str(), Some(32))));
+    assert_eq!(queue.queued_legacy_owner_for_dedup_key(&key), Some((second_id.as_str(), Some(32))));
+}
+
+#[tokio::test]
+async fn missing_selected_token_or_inconsistent_index_stays_unknown() {
+    let manager = HealManager::new_without_root_recovery_for_test(Arc::new(MockStorage), None);
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let second = object_request(HealRequestSource::Internal, HealPriority::High, true);
+    let second_id = second.id.clone();
+    {
+        let mut queue = manager.heal_queue.lock().await;
+        assert_eq!(queue.push_with_replacement_scope(first, false, Some(41)), QueuePushOutcome::Accepted);
+        assert_eq!(queue.push_with_replacement_scope(second, false, None), QueuePushOutcome::Accepted);
+        queue.pop().expect("first holder should leave");
+        assert_eq!(queue.queued_scanner_owner_for_dedup_key(&key), Some((second_id.as_str(), None)));
+    }
+    let receipt = manager
+        .submit_heal_request_with_observation_and_alias(
+            object_request(HealRequestSource::Scanner, HealPriority::High, false),
+            false,
+        )
+        .await
+        .expect("merge into owner without an observation token");
+    assert_eq!(receipt.result, HealAdmissionResult::Merged);
+    assert_eq!(receipt.task_id, second_id);
+    assert_eq!(receipt.observation_id, None);
+
+    let mut queue = PriorityHealQueue::new();
+    let first = object_request(HealRequestSource::Scanner, HealPriority::High, false);
+    let key = PriorityHealQueue::make_dedup_key(&first);
+    let second = object_request(HealRequestSource::Internal, HealPriority::High, true);
+    assert_eq!(queue.push_with_replacement_scope(first, false, Some(51)), QueuePushOutcome::Accepted);
+    assert_eq!(queue.push_with_replacement_scope(second, false, Some(52)), QueuePushOutcome::Accepted);
+    let ScannerQueuedOwners::Indexed(owners) = &mut queue.dedup_keys.get_mut(&key).expect("key").scanner_queued_owners else {
+        panic!("forced holder should create an index");
+    };
+    let first_sequence = *owners.first_key_value().expect("first indexed holder").0;
+    assert!(owners.remove(&first_sequence).is_some());
+    assert_eq!(queue.queued_scanner_owner_for_dedup_key(&key), None);
+    queue.pop().expect("first holder should leave");
+    assert_eq!(queue.queued_scanner_owner_for_dedup_key(&key), None);
+    assert_eq!(queue.queued_legacy_owner_for_dedup_key(&key).and_then(|(_, token)| token), None);
+}

crates/heal/src/heal/manager/tests/root_recovery.rs

@@ -448,6 +448,7 @@ async fn root_recovery_retry_cancellation_preserves_previous_attempt_outcome() {
     manager.retrying_heals.lock().await.insert(
         request.id.clone(),
         RetryingHeal {
+            observation_id: None,
             request: request.clone(),
             error: "retryable".to_string(),
             cancel_token: CancellationToken::new(),
@@ -2153,6 +2154,30 @@ async fn root_recovery_cluster_rejects_inventory_without_checkpoint_headroom() {
     );
 }
 
+#[tokio::test]
+async fn root_recovery_replayed_queue_owner_gets_a_fresh_in_process_observation_identity() {
+    let (_temp, disk) = recovery_disk().await;
+    let manager = recovery_manager(vec![disk.clone()]);
+    let request = root_request();
+    let first = manager
+        .submit_heal_request_with_observation_and_alias(request.clone(), false)
+        .await
+        .expect("persisted admission");
+    assert_eq!(first.result, HealAdmissionResult::Accepted);
+    assert!(first.observation_id.is_some());
+    drop(manager);
+
+    let replayed = recovery_manager(vec![disk]);
+    replayed.replay_root_heals().await.expect("replay persisted root");
+    let recovered_id = replayed
+        .heal_queue
+        .lock()
+        .await
+        .queued_observation_for_request_id(&request.id);
+    assert!(recovered_id.is_some());
+    assert_ne!(recovered_id, first.observation_id);
+}
+
 #[tokio::test]
 async fn root_recovery_queued_owner_is_not_priority_displaced() {
     let (_temp, disk) = recovery_disk().await;

crates/heal/src/heal/task.rs

@@ -413,6 +413,8 @@ pub struct HealResultWindow {
 pub struct HealTask {
     /// Task ID
     pub id: String,
+    /// Process-local diagnostic identity; never persisted or part of a request.
+    pub(crate) observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
     /// Heal type
     pub heal_type: HealType,
     pub bucket_incarnation_id: Option<Uuid>,
@@ -494,6 +496,7 @@ impl HealTask {
     pub fn from_request(request: HealRequest, storage: Arc<dyn HealStorageAPI>) -> Self {
         Self {
             id: request.id,
+            observation_id: None,
             heal_type: request.heal_type,
             bucket_incarnation_id: request.bucket_incarnation_id,
             expected_mrf_bucket_incarnation_id: request.expected_mrf_bucket_incarnation_id,
@@ -529,6 +532,14 @@ impl HealTask {
         }
     }
 
+    pub(crate) fn with_observation_id(
+        mut self,
+        observation_id: Option<rustfs_heal_contracts::completion::HealObservationId>,
+    ) -> Self {
+        self.observation_id = observation_id;
+        self
+    }
+
     pub fn retry_request(&self) -> HealRequest {
         HealRequest {
             id: self.id.clone(),

crates/heal/src/lib.rs

@@ -280,12 +280,12 @@ pub async fn init_heal_manager_with_workload_provider(
             .is_some_and(|hook| hook.fail_channel_init.load(Ordering::SeqCst));
         #[cfg(not(test))]
         let force_channel_failure = false;
-        let channel_receiver = if force_channel_failure {
-            Err("forced heal channel initialization failure")
-        } else {
-            rustfs_heal_contracts::heal_channel::init_heal_channels()
-        };
-        let (receiver, receipt_receiver) = match channel_receiver {
+        if force_channel_failure {
+            stop_initializing_manager(&heal_manager).await?;
+            return Err(Error::Config("forced heal channel initialization failure".to_string()));
+        }
+        let channel_receiver = rustfs_heal_contracts::heal_channel::init_heal_channels_with_observations();
+        let (receiver, receipt_receiver, observed_receiver) = match channel_receiver {
             Ok(receivers) => receivers,
             Err(err) => {
                 stop_initializing_manager(&heal_manager).await?;
@@ -302,7 +302,10 @@ pub async fn init_heal_manager_with_workload_provider(
 
         tokio::spawn(async move {
             let mut processor = channel_processor.lock().await;
-            if let Err(e) = processor.start_with_receipts(receiver, receipt_receiver).await {
+            if let Err(e) = processor
+                .start_with_observed_receipts(receiver, receipt_receiver, observed_receiver)
+                .await
+            {
                 error!(
                     target: "rustfs::heal",
                     event = EVENT_HEAL_RUNTIME_STATE,

crates/scanner/src/heal_completion.rs

@@ -17,8 +17,8 @@
 
 use metrics::{counter, gauge};
 use rustfs_heal_contracts::{
-    completion::{HealCompletion, MAX_COMPLETION_IDENTITY_BYTES, subscribe_heal_completions},
-    heal_channel::{HealAdmissionReceipt, HealChannelRequest, HealScanMode},
+    completion::{MAX_COMPLETION_IDENTITY_BYTES, ObservedHealCompletion, subscribe_observed_heal_completions},
+    heal_channel::{HealChannelRequest, HealObservationChannelError, HealScanMode, ObservedHealAdmissionReceipt},
     outcome::{HealAbortReason, HealExecutionOutcome, HealObjectDisposition, HealObjectIdentity, HealObjectKind},
 };
 use serde::Serialize;
@@ -30,6 +30,7 @@ use std::{
 use tokio::sync::{broadcast, mpsc};
 
 const MAX_PENDING: usize = 1024;
+const MAX_PENDING_GROUPS: usize = MAX_PENDING;
 const MAX_RECENT: usize = 1024;
 const PENDING_TTL: Duration = Duration::from_secs(60 * 60);
 const RECENT_TTL: Duration = Duration::from_secs(10 * 60);
@@ -122,18 +123,46 @@ impl Candidate {
             count: 1,
         })
     }
+
+    fn has_same_semantics(&self, other: &Self) -> bool {
+        self.identity == other.identity && self.mode == other.mode && self.dry_run == other.dry_run
+    }
+}
+
+struct Pending {
+    // Keep the common single-group case inline.
+    first: Candidate,
+    others: Vec<Candidate>,
+}
+
+impl Pending {
+    fn iter(&self) -> impl Iterator<Item = &Candidate> {
+        std::iter::once(&self.first).chain(self.others.iter())
+    }
+
+    fn into_candidates(self) -> impl Iterator<Item = Candidate> {
+        std::iter::once(self.first).chain(self.others)
+    }
 }
 
 struct Recent {
-    completion: Arc<HealCompletion>,
+    completion: Arc<ObservedHealCompletion>,
     counted: bool,
 }
 
+#[derive(Clone, Debug, Hash, PartialEq, Eq)]
+struct ObservationKey {
+    task_id: String,
+    observation_id: rustfs_heal_contracts::completion::HealObservationId,
+}
+
 #[derive(Default)]
 struct Observations {
-    pending: HashMap<String, Candidate>,
-    recent: HashMap<String, Recent>,
-    recent_order: VecDeque<(Instant, String)>,
+    pending: HashMap<ObservationKey, Pending>,
+    // The group bound applies across all observation keys.
+    pending_groups: usize,
+    recent: HashMap<ObservationKey, Recent>,
+    recent_order: VecDeque<(Instant, ObservationKey)>,
     // All keys come from fixed execution/disposition/scope/mode labels, never task or object identities.
     terminal_counts: BTreeMap<(&'static str, &'static str, &'static str, &'static str), u64>,
     terminal_tasks: u64,
@@ -183,17 +212,7 @@ impl Settlement {
             "insufficient_scan"
         } else {
             match (candidate.identity.as_ref(), completion.object.as_ref()) {
-                (Some(expected), Some(actual)) if expected != &actual.identity => "identity_mismatch",
-                (Some(expected), Some(_))
-                    if expected.bucket_incarnation_id.is_some_and(|id| !id.is_nil())
-                        && expected.pool_index.is_some()
-                        && expected.set_index.is_some()
-                        && expected.version_id.as_ref().is_some_and(|version| !version.is_empty()) =>
-                {
-                    // Even an exact version and VerifiedHealthy do not bind the
-                    // candidate's content and leader epoch with today's contract.
-                    "content_and_leader_unknown"
-                }
+                (Some(expected), Some(actual)) => Self::identity_scope(expected, &actual.identity),
                 _ => "identity_unknown",
             }
         };
@@ -209,6 +228,60 @@ impl Settlement {
         }
     }
 
+    fn identity_scope(expected: &HealObjectIdentity, actual: &HealObjectIdentity) -> &'static str {
+        fn known_version(version: Option<&str>) -> Option<uuid::Uuid> {
+            version
+                .and_then(|id| uuid::Uuid::parse_str(id).ok())
+                .filter(|id| !id.is_nil())
+        }
+        let expected_bucket = (!expected.bucket.is_empty()).then_some(expected.bucket.as_str());
+        let actual_bucket = (!actual.bucket.is_empty()).then_some(actual.bucket.as_str());
+        let expected_object = (!expected.object.is_empty()).then_some(expected.object.as_str());
+        let actual_object = (!actual.object.is_empty()).then_some(actual.object.as_str());
+        let expected_version = known_version(expected.version_id.as_deref());
+        let actual_version = known_version(actual.version_id.as_deref());
+        let expected_incarnation = expected.bucket_incarnation_id.filter(|id| !id.is_nil());
+        let actual_incarnation = actual.bucket_incarnation_id.filter(|id| !id.is_nil());
+
+        if expected.kind != actual.kind
+            || expected_bucket.zip(actual_bucket).is_some_and(|(left, right)| left != right)
+            || expected_object.zip(actual_object).is_some_and(|(left, right)| left != right)
+            || expected_version
+                .zip(actual_version)
+                .is_some_and(|(left, right)| left != right)
+            || expected_incarnation
+                .zip(actual_incarnation)
+                .is_some_and(|(left, right)| left != right)
+            || expected
+                .pool_index
+                .zip(actual.pool_index)
+                .is_some_and(|(left, right)| left != right)
+            || expected
+                .set_index
+                .zip(actual.set_index)
+                .is_some_and(|(left, right)| left != right)
+        {
+            "identity_mismatch"
+        } else if expected_bucket.is_none()
+            || actual_bucket.is_none()
+            || expected_object.is_none()
+            || actual_object.is_none()
+            || expected_version.is_none()
+            || actual_version.is_none()
+            || expected_incarnation.is_none()
+            || actual_incarnation.is_none()
+            || expected.pool_index.is_none()
+            || actual.pool_index.is_none()
+            || expected.set_index.is_none()
+            || actual.set_index.is_none()
+        {
+            "identity_unknown"
+        } else {
+            // Matching identities still do not bind content or leader epoch.
+            "content_and_leader_unknown"
+        }
+    }
+
     fn record(&self) {
         counter!("rustfs_scanner_heal_candidate_terminal_total",
             "disposition" => self.disposition, "scope" => self.scope, "scan_mode" => self.mode.as_str())
@@ -240,50 +313,78 @@ impl Observations {
         self.record_unknown(settlement.scope, settlement.candidates);
     }
 
-    fn admit(&mut self, task_id: String, candidate: Candidate) -> Option<Settlement> {
-        if let Some(recent) = self.recent.get_mut(&task_id) {
+    fn admit(&mut self, key: ObservationKey, candidate: Candidate) -> Option<Settlement> {
+        if Instant::now().saturating_duration_since(candidate.first_seen) >= PENDING_TTL {
+            self.record_unknown("expired", candidate.count);
+            return None;
+        }
+        if let Some(recent) = self.recent.get_mut(&key) {
             let settlement = Settlement::new(candidate, recent);
             self.record_settlement(&settlement);
             return Some(settlement);
         }
-        if let Some(pending) = self.pending.get_mut(&task_id) {
-            pending.count = pending.count.saturating_add(candidate.count);
-            if pending.identity != candidate.identity {
-                pending.identity = None;
+        if let Some(pending) = self.pending.get_mut(&key) {
+            if pending.first.has_same_semantics(&candidate) {
+                pending.first.count = pending.first.count.saturating_add(candidate.count);
+                pending.first.first_seen = pending.first.first_seen.min(candidate.first_seen);
+            } else if let Some(group) = pending.others.iter_mut().find(|group| group.has_same_semantics(&candidate)) {
+                group.count = group.count.saturating_add(candidate.count);
+                group.first_seen = group.first_seen.min(candidate.first_seen);
+            } else if self.pending_groups < MAX_PENDING_GROUPS {
+                pending.others.push(candidate);
+                self.pending_groups += 1;
+            } else {
+                self.record_unknown("pending_groups_full", candidate.count);
             }
-            if candidate.mode == HealScanMode::Deep {
-                pending.mode = HealScanMode::Deep;
-            }
-            pending.dry_run |= candidate.dry_run;
-        } else if self.pending.len() < MAX_PENDING {
-            self.pending.insert(task_id, candidate);
-        } else {
+        } else if self.pending.len() >= MAX_PENDING {
             self.record_unknown("pending_full", candidate.count);
+        } else if self.pending_groups >= MAX_PENDING_GROUPS {
+            self.record_unknown("pending_groups_full", candidate.count);
+        } else {
+            self.pending.insert(
+                key,
+                Pending {
+                    first: candidate,
+                    others: Vec::new(),
+                },
+            );
+            self.pending_groups += 1;
         }
         None
     }
 
-    fn complete(&mut self, completion: Arc<HealCompletion>, now: Instant) -> Option<Settlement> {
-        if self.recent.contains_key(&completion.task_id) {
+    fn complete(&mut self, completion: Arc<ObservedHealCompletion>, now: Instant) -> Option<Settlement> {
+        let key = ObservationKey {
+            task_id: completion.task_id.clone(),
+            observation_id: completion.observation_id?,
+        };
+        if self.recent.contains_key(&key) {
             return None;
         }
-        let task_id = completion.task_id.clone();
         let mut recent = Recent {
             completion,
             counted: false,
         };
-        let settled = self
-            .pending
-            .remove(&task_id)
-            .map(|candidate| Settlement::new(candidate, &mut recent));
+        let mut settled = None;
+        if let Some(pending) = self.pending.remove(&key) {
+            self.pending_groups -= 1 + pending.others.len();
+            for candidate in pending.into_candidates() {
+                if now.saturating_duration_since(candidate.first_seen) >= PENDING_TTL {
+                    self.record_unknown("expired", candidate.count);
+                    continue;
+                }
+                let settlement = Settlement::new(candidate, &mut recent);
+                self.record_settlement(&settlement);
+                if settled.is_none() {
+                    settled = Some(settlement);
+                }
+            }
+        }
         if self.recent.len() == MAX_RECENT {
             self.evict_recent();
         }
-        self.recent_order.push_back((now, task_id.clone()));
-        self.recent.insert(task_id, recent);
-        if let Some(settlement) = &settled {
-            self.record_settlement(settlement);
-        }
+        self.recent_order.push_back((now, key.clone()));
+        self.recent.insert(key, recent);
         settled
     }
 
@@ -297,7 +398,9 @@ impl Observations {
         let candidates = self
             .pending
             .drain()
-            .fold(0u64, |count, (_, candidate)| count.saturating_add(candidate.count));
+            .flat_map(|(_, pending)| pending.into_candidates())
+            .fold(0u64, |count, candidate| count.saturating_add(candidate.count));
+        self.pending_groups = 0;
         if candidates > 0 {
             self.record_unknown("completion_lost", candidates);
         }
@@ -313,14 +416,32 @@ impl Observations {
 
     fn maintain(&mut self, now: Instant) {
         let mut expired = 0u64;
-        self.pending.retain(|_, candidate| {
-            if now.saturating_duration_since(candidate.first_seen) >= PENDING_TTL {
-                expired = expired.saturating_add(candidate.count);
-                false
-            } else {
-                true
+        let mut expired_groups = 0usize;
+        self.pending.retain(|_, pending| {
+            let previous_len = pending.others.len();
+            pending.others.retain(|candidate| {
+                if now.saturating_duration_since(candidate.first_seen) >= PENDING_TTL {
+                    expired = expired.saturating_add(candidate.count);
+                    expired_groups += 1;
+                    false
+                } else {
+                    true
+                }
+            });
+            if now.saturating_duration_since(pending.first.first_seen) >= PENDING_TTL {
+                expired = expired.saturating_add(pending.first.count);
+                expired_groups += 1;
+                if pending.others.is_empty() {
+                    return false;
+                }
+                pending.first = pending.others.remove(0);
             }
+            if pending.others.len() < previous_len {
+                pending.others.shrink_to_fit();
+            }
+            true
         });
+        self.pending_groups -= expired_groups;
         if expired > 0 {
             self.record_unknown("expired", expired);
         }
@@ -334,6 +455,7 @@ impl Observations {
         let oldest = self
             .pending
             .values()
+            .flat_map(Pending::iter)
             .map(|candidate| now.saturating_duration_since(candidate.first_seen))
             .max();
         gauge!("rustfs_scanner_heal_pending_tasks").set(self.pending.len() as f64);
@@ -341,7 +463,7 @@ impl Observations {
     }
 }
 
-type AdmissionSender = mpsc::Sender<(String, Candidate)>;
+type AdmissionSender = mpsc::Sender<(ObservationKey, Candidate)>;
 
 #[derive(Clone)]
 struct ObserverHandle {
@@ -371,7 +493,7 @@ fn observer_from(registry: &Mutex<Option<ObserverHandle>>) -> ObserverHandle {
     let state = Arc::new(Mutex::new(Observations::default()));
     let handle = {
         let (sender, mut admissions) = mpsc::channel(MAX_PENDING);
-        let mut completions = subscribe_heal_completions();
+        let mut completions = subscribe_observed_heal_completions();
         let observations = state.clone();
         tokio::spawn(async move {
             let mut tick = tokio::time::interval(Duration::from_secs(5));
@@ -445,12 +567,14 @@ fn observation_status_from(registry: &Mutex<Option<ObserverHandle>>) -> ScannerH
             observations
                 .pending
                 .values()
+                .flat_map(Pending::iter)
                 .fold(0u64, |count, candidate| count.saturating_add(candidate.count)),
         );
         let now = Instant::now();
         status.oldest_pending_seconds = observations
             .pending
             .values()
+            .flat_map(Pending::iter)
             .map(|candidate| now.saturating_duration_since(candidate.first_seen))
             .max()
             .map(|age| age.as_secs_f64());
@@ -489,11 +613,18 @@ pub(crate) fn prepare(request: &HealChannelRequest) -> Option<Candidate> {
     Candidate::from_request(request)
 }
 
-pub(crate) fn observe(candidate: Option<Candidate>, receipt: Result<&HealAdmissionReceipt, ()>) {
+pub(crate) fn observe(
+    candidate: Option<Candidate>,
+    receipt: Result<&ObservedHealAdmissionReceipt, &HealObservationChannelError>,
+) {
     observe_on(&observer(), candidate, receipt);
 }
 
-fn observe_on(observer: &ObserverHandle, candidate: Option<Candidate>, receipt: Result<&HealAdmissionReceipt, ()>) {
+fn observe_on(
+    observer: &ObserverHandle,
+    candidate: Option<Candidate>,
+    receipt: Result<&ObservedHealAdmissionReceipt, &HealObservationChannelError>,
+) {
     match receipt {
         Ok(receipt) if receipt.result.is_admitted() => {
             let Some(candidate) = candidate else {
@@ -505,11 +636,20 @@ fn observe_on(observer: &ObserverHandle, candidate: Option<Candidate>, receipt:
                 observer.record_unknown("missing_task_id", 1);
                 return;
             }
-            if observer.sender.try_send((task_id.clone(), candidate)).is_err() {
+            let Some(observation_id) = receipt.observation_id else {
+                observer.record_unknown("owner_generation_unknown", candidate.count);
+                return;
+            };
+            let key = ObservationKey {
+                task_id: task_id.clone(),
+                observation_id,
+            };
+            if observer.sender.try_send((key, candidate)).is_err() {
                 observer.record_unknown("observer_full_or_closed", 1);
             }
         }
-        _ => observer.record_unknown("not_admitted", 1),
+        Ok(_) => observer.record_unknown("not_admitted", 1),
+        Err(_) => observer.record_unknown("admission_unknown", 1),
     }
 }
 

crates/scanner/src/scanner_folder.rs

@@ -51,7 +51,7 @@ use rustfs_filemeta::{
 };
 use rustfs_heal_contracts::heal_channel::{
     HEAL_DELETE_DANGLING, HealAdmissionDropReason, HealAdmissionResult, HealChannelPriority, HealChannelRequest,
-    HealRequestSource, HealScanMode, send_heal_request_with_receipt,
+    HealRequestSource, HealScanMode, send_heal_request_with_observation,
 };
 use rustfs_scanner_metrics::metrics::{
     CloseDiskGuard, IlmAction, Metric, Metrics, ScannerReplicationRepairKind, ScannerSourceWorkUpdate, ScannerWorkSource,

crates/scanner/src/scanner_folder/item_actions.rs

@@ -481,7 +481,7 @@ pub(super) async fn send_scanner_heal_request(
     let priority = request.priority;
     let trace_context = scanner_heal_candidate_trace_context(&request);
     let candidate = crate::heal_completion::prepare(&request);
-    match send_heal_request_with_receipt(request).await {
+    match send_heal_request_with_observation(request).await {
         Ok(receipt) => {
             crate::heal_completion::observe(candidate, Ok(&receipt));
             let result = receipt.result;
@@ -501,7 +501,8 @@ pub(super) async fn send_scanner_heal_request(
             Ok(result)
         }
         Err(err) => {
-            crate::heal_completion::observe(candidate, Err(()));
+            crate::heal_completion::observe(candidate, Err(&err));
+            let err = err.to_string();
             counter!(
                 "rustfs_heal_candidate_enqueue_total",
                 "type" => candidate_type.to_string(),

docs/operations/scanner-runtime-controls.md

@@ -623,7 +623,7 @@ typed terminal result:
 
 | Metric | Meaning |
 |---|---|
-| `rustfs_scanner_heal_pending_tasks` | Canonical tasks awaiting a terminal observation. |
+| `rustfs_scanner_heal_pending_tasks` | Pending task ID and owner-generation pairs awaiting a terminal observation. |
 | `rustfs_scanner_heal_pending_oldest_seconds` | Age of the oldest retained pending candidate; refreshed every five seconds. |
 | `rustfs_scanner_heal_candidate_terminal_total` | Associated candidates, labeled by object `disposition`, expected `scan_mode`, and unresolved `scope`. |
 | `rustfs_scanner_heal_task_terminal_observations_total` | Associated task observations, deduplicated within the bounded recent history. This is not an execution count. |
@@ -640,16 +640,25 @@ verified-byte or full-bucket coverage counter is advanced here.
 The scanner status response also exposes `heal_observation` without requiring
 a metrics exporter. Reading status does not start an observer. `state` is
 `not_started`, `active`, or `stopped`; unavailable pending counts are null.
-`retained_pending_tasks` counts canonical IDs in the existing bounded map,
-while `retained_pending_candidates` counts their associated discoveries.
+`retained_pending_tasks` counts distinct canonical task ID and process-local
+owner-generation pairs in the bounded map. Different generations of the same
+task ID count separately. `retained_pending_candidates` counts their associated
+discoveries. The JSON field names are unchanged. The pending-tasks metric uses
+the same pair count when periodically refreshed, so it can lag the status.
 `queued_admissions` samples the local admission channel and is not an atomic
 cluster backlog. `terminal_task_observations_total` keeps the same bounded
 deduplication semantics as the exporter counter.
 
 `terminal_candidates` preserves execution, object disposition, scan mode, and
 unresolved scope. `unknown_candidates` includes admission rejection, overflow,
-loss, expiry, and missing terminal proof. These categories overlap: a completed
-task with a repaired or verified-healthy object can still have unknown scanner
+loss, expiry, and missing terminal proof. The `not_admitted` reason covers an
+explicit `Full` or `Dropped` decision. The `admission_unknown` reason means no
+decision was received because of a channel or processor error. A lost reply
+does not establish whether work was admitted; a failure known to occur before
+enqueue separately rules out submission. Both reasons remain part of the
+unknown total. Monitoring that filters by reason must include the new
+`admission_unknown` label to retain those errors. These categories overlap: a
+completed task with a repaired or verified-healthy object can still have unknown scanner
 integrity. `integrity_state` therefore remains `unknown`, including when retained
 pending is zero. `lost_completion_notifications` counts skipped messages, not
 objects. Counts belong to the named local observer `generation`; runtime