diff --git a/weed/command/backup.go b/weed/command/backup.go
index 207df770b..4c5a2d820 100644
--- a/weed/command/backup.go
+++ b/weed/command/backup.go
@@ -72,7 +72,7 @@ func runBackup(cmd *Command, args []string) bool {
 	vid := needle.VolumeId(*s.volumeId)
 
 	// find volume location, replication, ttl info
-	lookup, err := operation.Lookup(func() string { return *s.master }, vid.String())
+	lookup, err := operation.LookupVolumeId(func() string { return *s.master }, grpcDialOption, vid.String())
 	if err != nil {
 		fmt.Printf("Error looking up volume %d: %v\n", vid, err)
 		return true
diff --git a/weed/operation/lookup.go b/weed/operation/lookup.go
index 0372e47b0..ea68f8763 100644
--- a/weed/operation/lookup.go
+++ b/weed/operation/lookup.go
@@ -79,16 +79,21 @@ func LookupFileId(masterFn GetMasterFn, fileId string) (fullUrl string, err erro
 	return "http://" + lookup.Locations[rand.Intn(len(lookup.Locations))].Url + "/" + fileId, nil
 }
 
+func LookupVolumeId(masterFn GetMasterFn, grpcDialOption grpc.DialOption, vid string) (*LookupResult, error) {
+	results, err := LookupVolumeIds(masterFn, grpcDialOption, []string{vid})
+	return results[vid], err
+}
+
 // LookupVolumeIds find volume locations by cache and actual lookup
-func LookupVolumeIds(masterFn GetMasterFn, grpcDialOption grpc.DialOption, vids []string) (map[string]LookupResult, error) {
-	ret := make(map[string]LookupResult)
+func LookupVolumeIds(masterFn GetMasterFn, grpcDialOption grpc.DialOption, vids []string) (map[string]*LookupResult, error) {
+	ret := make(map[string]*LookupResult)
 	var unknown_vids []string
 
 	//check vid cache first
 	for _, vid := range vids {
-		locations, cache_err := vc.Get(vid)
-		if cache_err == nil {
-			ret[vid] = LookupResult{VolumeId: vid, Locations: locations}
+		locations, cacheErr := vc.Get(vid)
+		if cacheErr == nil {
+			ret[vid] = &LookupResult{VolumeId: vid, Locations: locations}
 		} else {
 			unknown_vids = append(unknown_vids, vid)
 		}
@@ -122,7 +127,7 @@ func LookupVolumeIds(masterFn GetMasterFn, grpcDialOption grpc.DialOption, vids
 			if vidLocations.Error != "" {
 				vc.Set(vidLocations.VolumeId, locations, 10*time.Minute)
 			}
-			ret[vidLocations.VolumeId] = LookupResult{
+			ret[vidLocations.VolumeId] = &LookupResult{
 				VolumeId:  vidLocations.VolumeId,
 				Locations: locations,
 				Error:     vidLocations.Error,
diff --git a/weed/operation/tail_volume.go b/weed/operation/tail_volume.go
index 79a5b3812..e3f2c0664 100644
--- a/weed/operation/tail_volume.go
+++ b/weed/operation/tail_volume.go
@@ -13,7 +13,7 @@ import (
 
 func TailVolume(masterFn GetMasterFn, grpcDialOption grpc.DialOption, vid needle.VolumeId, sinceNs uint64, timeoutSeconds int, fn func(n *needle.Needle) error) error {
 	// find volume location, replication, ttl info
-	lookup, err := Lookup(masterFn, vid.String())
+	lookup, err := LookupVolumeId(masterFn, grpcDialOption, vid.String())
 	if err != nil {
 		return fmt.Errorf("look up volume %d: %v", vid, err)
 	}
diff --git a/weed/server/volume_server_handlers_read.go b/weed/server/volume_server_handlers_read.go
index 8602b0854..29428730e 100644
--- a/weed/server/volume_server_handlers_read.go
+++ b/weed/server/volume_server_handlers_read.go
@@ -65,7 +65,7 @@ func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request)
 			w.WriteHeader(http.StatusNotFound)
 			return
 		}
-		lookupResult, err := operation.Lookup(vs.GetMaster, volumeId.String())
+		lookupResult, err := operation.LookupVolumeId(vs.GetMaster, vs.grpcDialOption, volumeId.String())
 		glog.V(2).Infoln("volume", volumeId, "found on", lookupResult, "error", err)
 		if err != nil || len(lookupResult.Locations) <= 0 {
 			glog.V(0).Infoln("lookup error:", err, r.URL.Path)
diff --git a/weed/server/volume_server_handlers_write.go b/weed/server/volume_server_handlers_write.go
index aeb7d6e65..bda8b986e 100644
--- a/weed/server/volume_server_handlers_write.go
+++ b/weed/server/volume_server_handlers_write.go
@@ -53,7 +53,7 @@ func (vs *VolumeServer) PostHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	ret := operation.UploadResult{}
-	isUnchanged, writeError := topology.ReplicatedWrite(vs.GetMaster, vs.store, volumeId, reqNeedle, r)
+	isUnchanged, writeError := topology.ReplicatedWrite(vs.GetMaster, vs.grpcDialOption, vs.store, volumeId, reqNeedle, r)
 
 	// http 204 status code does not allow body
 	if writeError == nil && isUnchanged {
@@ -146,7 +146,7 @@ func (vs *VolumeServer) DeleteHandler(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	_, err := topology.ReplicatedDelete(vs.GetMaster, vs.store, volumeId, n, r)
+	_, err := topology.ReplicatedDelete(vs.GetMaster, vs.grpcDialOption, vs.store, volumeId, n, r)
 
 	writeDeleteResult(err, count, w, r)
 
diff --git a/weed/topology/store_replicate.go b/weed/topology/store_replicate.go
index 6d68bb26f..061c5a12c 100644
--- a/weed/topology/store_replicate.go
+++ b/weed/topology/store_replicate.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"google.golang.org/grpc"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -18,7 +19,7 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/util"
 )
 
-func ReplicatedWrite(masterFn operation.GetMasterFn, s *storage.Store, volumeId needle.VolumeId, n *needle.Needle, r *http.Request) (isUnchanged bool, err error) {
+func ReplicatedWrite(masterFn operation.GetMasterFn, grpcDialOption grpc.DialOption, s *storage.Store, volumeId needle.VolumeId, n *needle.Needle, r *http.Request) (isUnchanged bool, err error) {
 
 	//check JWT
 	jwt := security.GetJwt(r)
@@ -27,7 +28,7 @@ func ReplicatedWrite(masterFn operation.GetMasterFn, s *storage.Store, volumeId
 	var remoteLocations []operation.Location
 	if r.FormValue("type") != "replicate" {
 		// this is the initial request
-		remoteLocations, err = getWritableRemoteReplications(s, volumeId, masterFn)
+		remoteLocations, err = getWritableRemoteReplications(s, grpcDialOption, volumeId, masterFn)
 		if err != nil {
 			glog.V(0).Infoln(err)
 			return
@@ -92,16 +93,14 @@ func ReplicatedWrite(masterFn operation.GetMasterFn, s *storage.Store, volumeId
 	return
 }
 
-func ReplicatedDelete(masterFn operation.GetMasterFn, store *storage.Store,
-	volumeId needle.VolumeId, n *needle.Needle,
-	r *http.Request) (size types.Size, err error) {
+func ReplicatedDelete(masterFn operation.GetMasterFn, grpcDialOption grpc.DialOption, store *storage.Store, volumeId needle.VolumeId, n *needle.Needle, r *http.Request) (size types.Size, err error) {
 
 	//check JWT
 	jwt := security.GetJwt(r)
 
 	var remoteLocations []operation.Location
 	if r.FormValue("type") != "replicate" {
-		remoteLocations, err = getWritableRemoteReplications(store, volumeId, masterFn)
+		remoteLocations, err = getWritableRemoteReplications(store, grpcDialOption, volumeId, masterFn)
 		if err != nil {
 			glog.V(0).Infoln(err)
 			return
@@ -161,8 +160,7 @@ func DistributedOperation(locations []operation.Location, op func(location opera
 	return ret.Error()
 }
 
-func getWritableRemoteReplications(s *storage.Store, volumeId needle.VolumeId, masterFn operation.GetMasterFn) (
-	remoteLocations []operation.Location, err error) {
+func getWritableRemoteReplications(s *storage.Store, grpcDialOption grpc.DialOption, volumeId needle.VolumeId, masterFn operation.GetMasterFn) (remoteLocations []operation.Location, err error) {
 
 	v := s.GetVolume(volumeId)
 	if v != nil && v.ReplicaPlacement.GetCopyCount() == 1 {
@@ -170,7 +168,7 @@ func getWritableRemoteReplications(s *storage.Store, volumeId needle.VolumeId, m
 	}
 
 	// not on local store, or has replications
-	lookupResult, lookupErr := operation.Lookup(masterFn, volumeId.String())
+	lookupResult, lookupErr := operation.LookupVolumeId(masterFn, grpcDialOption, volumeId.String())
 	if lookupErr == nil {
 		selfUrl := s.Ip + ":" + strconv.Itoa(s.Port)
 		for _, location := range lookupResult.Locations {