diff --git a/weed/s3api/s3acl/acl_helper.go b/weed/s3api/s3acl/acl_helper.go
index e54e67556..bb956368e 100644
--- a/weed/s3api/s3acl/acl_helper.go
+++ b/weed/s3api/s3acl/acl_helper.go
@@ -411,6 +411,8 @@ func AssembleEntryWithAcp(objectEntry *filer_pb.Entry, objectOwner string, grant
 
 	if len(objectOwner) > 0 {
 		objectEntry.Extended[s3_constants.ExtAmzOwnerKey] = []byte(objectOwner)
+	} else {
+		delete(objectEntry.Extended, s3_constants.ExtAmzOwnerKey)
 	}
 
 	if len(grants) > 0 {
@@ -420,6 +422,8 @@ func AssembleEntryWithAcp(objectEntry *filer_pb.Entry, objectOwner string, grant
 			return s3err.ErrInvalidRequest
 		}
 		objectEntry.Extended[s3_constants.ExtAmzAclKey] = grantsBytes
+	} else {
+		delete(objectEntry.Extended, s3_constants.ExtAmzAclKey)
 	}
 
 	return s3err.ErrNone
diff --git a/weed/s3api/s3acl/acl_helper_test.go b/weed/s3api/s3acl/acl_helper_test.go
index efc137989..ce177595b 100644
--- a/weed/s3api/s3acl/acl_helper_test.go
+++ b/weed/s3api/s3acl/acl_helper_test.go
@@ -487,46 +487,44 @@ func TestDetermineReqGrants(t *testing.T) {
 
 func TestAssembleEntryWithAcp(t *testing.T) {
 	defaultOwner := "admin"
-	{
-		//case1
-		expectOwner := "accountS"
-		expectGrants := []*s3.Grant{
-			{
-				Permission: &s3_constants.PermissionRead,
-				Grantee: &s3.Grantee{
-					Type: &s3_constants.GrantTypeGroup,
-					ID:   &s3account.AccountAdmin.Id,
-					URI:  &s3_constants.GranteeGroupAllUsers,
-				},
+
+	//case1
+	//assemble with non-empty grants
+	expectOwner := "accountS"
+	expectGrants := []*s3.Grant{
+		{
+			Permission: &s3_constants.PermissionRead,
+			Grantee: &s3.Grantee{
+				Type: &s3_constants.GrantTypeGroup,
+				ID:   &s3account.AccountAdmin.Id,
+				URI:  &s3_constants.GranteeGroupAllUsers,
 			},
-		}
-		entry := &filer_pb.Entry{}
-		AssembleEntryWithAcp(entry, expectOwner, expectGrants)
+		},
+	}
+	entry := &filer_pb.Entry{}
+	AssembleEntryWithAcp(entry, expectOwner, expectGrants)
 
-		resultOwner := GetAcpOwner(entry.Extended, defaultOwner)
-		if resultOwner != expectOwner {
-			t.Fatalf("owner not expect")
-		}
+	resultOwner := GetAcpOwner(entry.Extended, defaultOwner)
+	if resultOwner != expectOwner {
+		t.Fatalf("owner not expect")
+	}
 
-		resultGrants := GetAcpGrants(entry.Extended)
-		if !grantsEquals(resultGrants, expectGrants) {
-			t.Fatal("grants not expect")
-		}
+	resultGrants := GetAcpGrants(entry.Extended)
+	if !grantsEquals(resultGrants, expectGrants) {
+		t.Fatal("grants not expect")
 	}
-	{
-		//case2
-		entry := &filer_pb.Entry{}
-		AssembleEntryWithAcp(entry, "", nil)
 
-		resultOwner := GetAcpOwner(entry.Extended, defaultOwner)
-		if resultOwner != defaultOwner {
-			t.Fatalf("owner not expect")
-		}
+	//case2
+	//assemble with empty grants (override)
+	AssembleEntryWithAcp(entry, "", nil)
+	resultOwner = GetAcpOwner(entry.Extended, defaultOwner)
+	if resultOwner != defaultOwner {
+		t.Fatalf("owner not expect")
+	}
 
-		resultGrants := GetAcpGrants(entry.Extended)
-		if len(resultGrants) != 0 {
-			t.Fatal("grants not expect")
-		}
+	resultGrants = GetAcpGrants(entry.Extended)
+	if len(resultGrants) != 0 {
+		t.Fatal("grants not expect")
 	}
 
 }
diff --git a/weed/server/volume_grpc_vacuum.go b/weed/server/volume_grpc_vacuum.go
index 5252584e1..296760ba6 100644
--- a/weed/server/volume_grpc_vacuum.go
+++ b/weed/server/volume_grpc_vacuum.go
@@ -2,6 +2,9 @@ package weed_server
 
 import (
 	"context"
+	"github.com/seaweedfs/seaweedfs/weed/stats"
+	"strconv"
+	"time"
 
 	"github.com/prometheus/procfs"
 	"github.com/seaweedfs/seaweedfs/weed/glog"
@@ -29,6 +32,10 @@ func (vs *VolumeServer) VacuumVolumeCheck(ctx context.Context, req *volume_serve
 }
 
 func (vs *VolumeServer) VacuumVolumeCompact(req *volume_server_pb.VacuumVolumeCompactRequest, stream volume_server_pb.VolumeServer_VacuumVolumeCompactServer) error {
+	start := time.Now()
+	defer func(start time.Time) {
+		stats.VolumeServerVacuumingHistogram.WithLabelValues("compact").Observe(time.Since(start).Seconds())
+	}(start)
 
 	resp := &volume_server_pb.VacuumVolumeCompactResponse{}
 	reportInterval := int64(1024 * 1024 * 128)
@@ -51,12 +58,13 @@ func (vs *VolumeServer) VacuumVolumeCompact(req *volume_server_pb.VacuumVolumeCo
 		return true
 	})
 
+	stats.VolumeServerVacuumingCompactCounter.WithLabelValues(strconv.FormatBool(err == nil && sendErr == nil)).Inc()
 	if err != nil {
-		glog.Errorf("compact volume %d: %v", req.VolumeId, err)
+		glog.Errorf("failed compact volume %d: %v", req.VolumeId, err)
 		return err
 	}
 	if sendErr != nil {
-		glog.Errorf("compact volume %d report progress: %v", req.VolumeId, sendErr)
+		glog.Errorf("failed compact volume %d report progress: %v", req.VolumeId, sendErr)
 		return sendErr
 	}
 
@@ -66,16 +74,21 @@ func (vs *VolumeServer) VacuumVolumeCompact(req *volume_server_pb.VacuumVolumeCo
 }
 
 func (vs *VolumeServer) VacuumVolumeCommit(ctx context.Context, req *volume_server_pb.VacuumVolumeCommitRequest) (*volume_server_pb.VacuumVolumeCommitResponse, error) {
+	start := time.Now()
+	defer func(start time.Time) {
+		stats.VolumeServerVacuumingHistogram.WithLabelValues("commit").Observe(time.Since(start).Seconds())
+	}(start)
 
 	resp := &volume_server_pb.VacuumVolumeCommitResponse{}
 
 	readOnly, err := vs.store.CommitCompactVolume(needle.VolumeId(req.VolumeId))
 
 	if err != nil {
-		glog.Errorf("commit volume %d: %v", req.VolumeId, err)
+		glog.Errorf("failed commit volume %d: %v", req.VolumeId, err)
 	} else {
 		glog.V(1).Infof("commit volume %d", req.VolumeId)
 	}
+	stats.VolumeServerVacuumingCommitCounter.WithLabelValues(strconv.FormatBool(err == nil)).Inc()
 	resp.IsReadOnly = readOnly
 	return resp, err
 
@@ -88,7 +101,7 @@ func (vs *VolumeServer) VacuumVolumeCleanup(ctx context.Context, req *volume_ser
 	err := vs.store.CommitCleanupVolume(needle.VolumeId(req.VolumeId))
 
 	if err != nil {
-		glog.Errorf("cleanup volume %d: %v", req.VolumeId, err)
+		glog.Errorf("failed cleanup volume %d: %v", req.VolumeId, err)
 	} else {
 		glog.V(1).Infof("cleanup volume %d", req.VolumeId)
 	}
diff --git a/weed/stats/metrics.go b/weed/stats/metrics.go
index d1723fdc6..9f9c0c18d 100644
--- a/weed/stats/metrics.go
+++ b/weed/stats/metrics.go
@@ -137,6 +137,31 @@ var (
 			Help:      "Counter of volume server requests.",
 		}, []string{"type"})
 
+	VolumeServerVacuumingCompactCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: Namespace,
+			Subsystem: "volumeServer",
+			Name:      "vacuuming_compact_count",
+			Help:      "Counter of volume vacuuming Compact counter",
+		}, []string{"success"})
+
+	VolumeServerVacuumingCommitCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: Namespace,
+			Subsystem: "volumeServer",
+			Name:      "vacuuming_commit_count",
+			Help:      "Counter of volume vacuuming commit counter",
+		}, []string{"success"})
+
+	VolumeServerVacuumingHistogram = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: Namespace,
+			Subsystem: "volumeServer",
+			Name:      "vacuuming_seconds",
+			Help:      "Bucketed histogram of volume server vacuuming processing time.",
+			Buckets:   prometheus.ExponentialBuckets(0.0001, 2, 24),
+		}, []string{"type"})
+
 	VolumeServerRequestHistogram = prometheus.NewHistogramVec(
 		prometheus.HistogramOpts{
 			Namespace: Namespace,
@@ -223,6 +248,9 @@ func init() {
 
 	Gather.MustRegister(VolumeServerRequestCounter)
 	Gather.MustRegister(VolumeServerRequestHistogram)
+	Gather.MustRegister(VolumeServerVacuumingCompactCounter)
+	Gather.MustRegister(VolumeServerVacuumingCommitCounter)
+	Gather.MustRegister(VolumeServerVacuumingHistogram)
 	Gather.MustRegister(VolumeServerVolumeCounter)
 	Gather.MustRegister(VolumeServerMaxVolumeCounter)
 	Gather.MustRegister(VolumeServerReadOnlyVolumeGauge)
diff --git a/weed/storage/backend/disk_file.go b/weed/storage/backend/disk_file.go
index 7a3a40977..18dde8dca 100644
--- a/weed/storage/backend/disk_file.go
+++ b/weed/storage/backend/disk_file.go
@@ -69,6 +69,9 @@ func (df *DiskFile) Truncate(off int64) error {
 }
 
 func (df *DiskFile) Close() error {
+	if err := df.Sync(); err != nil {
+		return err
+	}
 	return df.File.Close()
 }
 
diff --git a/weed/storage/disk_location.go b/weed/storage/disk_location.go
index 6f938da8f..b3be04703 100644
--- a/weed/storage/disk_location.go
+++ b/weed/storage/disk_location.go
@@ -364,7 +364,7 @@ func (l *DiskLocation) VolumesLen() int {
 func (l *DiskLocation) SetStopping() {
 	l.volumesLock.Lock()
 	for _, v := range l.volumes {
-		v.SetStopping()
+		v.SyncToDisk()
 	}
 	l.volumesLock.Unlock()
 
diff --git a/weed/storage/erasure_coding/ec_volume.go b/weed/storage/erasure_coding/ec_volume.go
index aa1e15722..ddee742a8 100644
--- a/weed/storage/erasure_coding/ec_volume.go
+++ b/weed/storage/erasure_coding/ec_volume.go
@@ -125,6 +125,7 @@ func (ev *EcVolume) Close() {
 		ev.ecjFileAccessLock.Unlock()
 	}
 	if ev.ecxFile != nil {
+		_ = ev.ecxFile.Sync()
 		_ = ev.ecxFile.Close()
 		ev.ecxFile = nil
 	}
diff --git a/weed/storage/needle_map/memdb.go b/weed/storage/needle_map/memdb.go
index 7fb98dcea..463245cd1 100644
--- a/weed/storage/needle_map/memdb.go
+++ b/weed/storage/needle_map/memdb.go
@@ -86,7 +86,10 @@ func (cm *MemDb) SaveToIdx(idxName string) (ret error) {
 	if err != nil {
 		return
 	}
-	defer idxFile.Close()
+	defer func() {
+		idxFile.Sync()
+		idxFile.Close()
+	}()
 
 	return cm.AscendingVisit(func(value NeedleValue) error {
 		if value.Offset.IsZero() || value.Size.IsDeleted() {
diff --git a/weed/storage/volume.go b/weed/storage/volume.go
index 1a9c8bd24..ab8af91e2 100644
--- a/weed/storage/volume.go
+++ b/weed/storage/volume.go
@@ -180,21 +180,6 @@ func (v *Volume) DiskType() types.DiskType {
 	return v.location.DiskType
 }
 
-func (v *Volume) SetStopping() {
-	v.dataFileAccessLock.Lock()
-	defer v.dataFileAccessLock.Unlock()
-	if v.nm != nil {
-		if err := v.nm.Sync(); err != nil {
-			glog.Warningf("Volume SetStopping fail to sync volume idx %d", v.Id)
-		}
-	}
-	if v.DataBackend != nil {
-		if err := v.DataBackend.Sync(); err != nil {
-			glog.Warningf("Volume SetStopping fail to sync volume %d", v.Id)
-		}
-	}
-}
-
 func (v *Volume) SyncToDisk() {
 	v.dataFileAccessLock.Lock()
 	defer v.dataFileAccessLock.Unlock()
@@ -228,10 +213,9 @@ func (v *Volume) Close() {
 		v.nm = nil
 	}
 	if v.DataBackend != nil {
-		if err := v.DataBackend.Sync(); err != nil {
+		if err := v.DataBackend.Close(); err != nil {
 			glog.Warningf("Volume Close fail to sync volume %d", v.Id)
 		}
-		_ = v.DataBackend.Close()
 		v.DataBackend = nil
 		stats.VolumeServerVolumeCounter.WithLabelValues(v.Collection, "volume").Dec()
 	}
diff --git a/weed/storage/volume_vacuum.go b/weed/storage/volume_vacuum.go
index 47b0800eb..0eaca5ff4 100644
--- a/weed/storage/volume_vacuum.go
+++ b/weed/storage/volume_vacuum.go
@@ -55,10 +55,10 @@ func (v *Volume) Compact(preallocate int64, compactionBytePerSecond int64) error
 	v.lastCompactRevision = v.SuperBlock.CompactionRevision
 	glog.V(3).Infof("creating copies for volume %d ,last offset %d...", v.Id, v.lastCompactIndexOffset)
 	if err := v.DataBackend.Sync(); err != nil {
-		glog.V(0).Infof("compact fail to sync volume %d", v.Id)
+		glog.V(0).Infof("compact failed to sync volume %d", v.Id)
 	}
 	if err := v.nm.Sync(); err != nil {
-		glog.V(0).Infof("compact fail to sync volume idx %d", v.Id)
+		glog.V(0).Infof("compact failed to sync volume idx %d", v.Id)
 	}
 	return v.copyDataAndGenerateIndexFile(v.FileName(".cpd"), v.FileName(".cpx"), preallocate, compactionBytePerSecond)
 }
@@ -83,10 +83,10 @@ func (v *Volume) Compact2(preallocate int64, compactionBytePerSecond int64, prog
 		return fmt.Errorf("volume %d backend is empty remote:%v", v.Id, v.HasRemoteFile())
 	}
 	if err := v.DataBackend.Sync(); err != nil {
-		glog.V(0).Infof("compact2 fail to sync volume dat %d: %v", v.Id, err)
+		glog.V(0).Infof("compact2 failed to sync volume dat %d: %v", v.Id, err)
 	}
 	if err := v.nm.Sync(); err != nil {
-		glog.V(0).Infof("compact2 fail to sync volume idx %d: %v", v.Id, err)
+		glog.V(0).Infof("compact2 failed to sync volume idx %d: %v", v.Id, err)
 	}
 	return v.copyDataBasedOnIndexFile(
 		v.FileName(".dat"), v.FileName(".idx"),
@@ -120,7 +120,7 @@ func (v *Volume) CommitCompact() error {
 	}
 	if v.DataBackend != nil {
 		if err := v.DataBackend.Close(); err != nil {
-			glog.V(0).Infof("fail to close volume %d", v.Id)
+			glog.V(0).Infof("failed to close volume %d", v.Id)
 		}
 	}
 	v.DataBackend = nil
@@ -270,7 +270,11 @@ func (v *Volume) makeupDiff(newDatFileName, newIdxFileName, oldDatFileName, oldI
 		return fmt.Errorf("open idx file %s failed: %v", newIdxFileName, err)
 	}
 
-	defer idx.Close()
+	defer func() {
+		idx.Sync()
+		idx.Close()
+	}()
+
 	stat, err := idx.Stat()
 	if err != nil {
 		return fmt.Errorf("stat file %s: %v", idx.Name(), err)
@@ -387,9 +391,7 @@ func (scanner *VolumeFileScanner4Vacuum) VisitNeedle(n *needle.Needle, offset in
 }
 
 func (v *Volume) copyDataAndGenerateIndexFile(dstName, idxName string, preallocate int64, compactionBytePerSecond int64) (err error) {
-	var (
-		dst backend.BackendStorageFile
-	)
+	var dst backend.BackendStorageFile
 	if dst, err = backend.CreateVolumeFile(dstName, preallocate, 0); err != nil {
 		return err
 	}
@@ -493,7 +495,10 @@ func (v *Volume) copyDataBasedOnIndexFile(srcDatName, srcIdxName, dstDatName, da
 		glog.Errorf("cannot open Volume Index %s: %v", datIdxName, err)
 		return err
 	}
-	defer indexFile.Close()
+	defer func() {
+		indexFile.Sync()
+		indexFile.Close()
+	}()
 	if v.tmpNm != nil {
 		v.tmpNm.Close()
 		v.tmpNm = nil