feat(ilm): relocate hot objects across server pools by GET frequency

Keep NVMe/HDD pool pairs useful without remote tiering: promote objects that
are read often, demote previously moved objects once they go idle, and leave
the feature off until operators set a two-pool topology.

Signed-off-by: mr javad seydi <seydi.birjand@gmail.com>

cmd/data-scanner.go

@@ -899,6 +899,7 @@ type scannerItem struct {
 	objectName  string // Only the object name without prefixes.
 	replication replicationConfig
 	lifeCycle   *lifecycle.Lifecycle
+	poolIdx     int
 	Typ         fs.FileMode
 	heal        struct {
 		enabled bool
@@ -909,6 +910,7 @@ type scannerItem struct {
 
 type sizeSummary struct {
 	totalSize       int64
+	hotTierSize     int64
 	versions        uint64
 	deleteMarkers   uint64
 	replicatedSize  int64
@@ -1159,6 +1161,14 @@ eventLoop:
 		globalExpiryState.enqueueNoncurrentVersions(i.bucket, toDel, noncurrentEvents)
 	}
 	i.alertExcessiveVersions(remainingVersions, cumulativeSize)
+	if globalILMConfig.accessTieringEnabled() {
+		for idx, oi := range objInfos {
+			if oi.IsLatest && events[idx].Action == lifecycle.NoneAction {
+				applyAccessTransition(ctx, i, oi)
+				break
+			}
+		}
+	}
 }
 
 func evalActionFromLifecycle(ctx context.Context, lc lifecycle.Lifecycle, lr lock.Retention, rcfg *replication.Config, obj ObjectInfo) lifecycle.Event {
@@ -1474,6 +1484,8 @@ const (
 	ILMFreeVersionDelete = "ilm:free-version-delete"
 	// ILMTransition - audit trail for ILM transitioning.
 	ILMTransition = " ilm:transition"
+	// ILMAccessTier - audit trail for moving objects between server pools.
+	ILMAccessTier = "ilm:access-tier"
 )
 
 func auditLogLifecycle(ctx context.Context, oi ObjectInfo, event string, tags map[string]string, traceFn func(event string, metadata map[string]string, err error)) {
@@ -1485,6 +1497,8 @@ func auditLogLifecycle(ctx context.Context, oi ObjectInfo, event string, tags ma
 		apiName = "ILMFreeVersionDelete"
 	case ILMTransition:
 		apiName = "ILMTransition"
+	case ILMAccessTier:
+		apiName = "ILMAccessTier"
 	}
 	auditLogInternal(ctx, AuditLogOptions{
 		Event:     event,