diff --git a/go/filer/client_operations.go b/go/filer/client_operations.go
index 80ac51693..b3ccc633a 100644
--- a/go/filer/client_operations.go
+++ b/go/filer/client_operations.go
@@ -58,7 +58,7 @@ func call(server string, request ApiRequest, ret interface{}) error {
 	}
 	values := make(url.Values)
 	values.Add("request", string(b))
-	jsonBlob, err := util.Post("http://"+server+"/__api__", values)
+	jsonBlob, err := util.Post(server, "/__api__", values)
 	if err != nil {
 		return err
 	}
diff --git a/go/operation/assign_file_id.go b/go/operation/assign_file_id.go
index fa436b651..45ac5c362 100644
--- a/go/operation/assign_file_id.go
+++ b/go/operation/assign_file_id.go
@@ -31,7 +31,7 @@ func Assign(server string, count uint64, replication string, collection string,
 	if ttl != "" {
 		values.Add("ttl", ttl)
 	}
-	jsonBlob, err := util.Post("http://"+server+"/dir/assign", values)
+	jsonBlob, err := util.Post(server, "/dir/assign", values)
 	glog.V(2).Info("assign result :", string(jsonBlob))
 	if err != nil {
 		return nil, err
diff --git a/go/operation/delete_content.go b/go/operation/delete_content.go
index 9bd6654d7..a8cd46f71 100644
--- a/go/operation/delete_content.go
+++ b/go/operation/delete_content.go
@@ -97,7 +97,7 @@ func DeleteFiles(master string, fileIds []string) (*DeleteFilesResult, error) {
 			for _, fid := range fidList {
 				values.Add("fid", fid)
 			}
-			jsonBlob, err := util.Post("http://"+server+"/delete", values)
+			jsonBlob, err := util.Post(server, "/delete", values)
 			if err != nil {
 				ret.Errors = append(ret.Errors, err.Error()+" "+string(jsonBlob))
 				return
diff --git a/go/operation/list_masters.go b/go/operation/list_masters.go
index bda6f3c65..8aa1eae58 100644
--- a/go/operation/list_masters.go
+++ b/go/operation/list_masters.go
@@ -14,7 +14,7 @@ type ClusterStatusResult struct {
 }
 
 func ListMasters(server string) ([]string, error) {
-	jsonBlob, err := util.Get("http://" + server + "/cluster/status")
+	jsonBlob, err := util.Get(server, "/cluster/status", nil)
 	glog.V(2).Info("list masters result :", string(jsonBlob))
 	if err != nil {
 		return nil, err
diff --git a/go/operation/lookup.go b/go/operation/lookup.go
index 83ef55752..86a2ff760 100644
--- a/go/operation/lookup.go
+++ b/go/operation/lookup.go
@@ -63,7 +63,7 @@ func LookupNoCache(server string, vid string) (ret *LookupResult, err error) {
 func do_lookup(server string, vid string) (*LookupResult, error) {
 	values := make(url.Values)
 	values.Add("volumeId", vid)
-	jsonBlob, err := util.Post("http://"+server+"/dir/lookup", values)
+	jsonBlob, err := util.Post(server, "/dir/lookup", values)
 	if err != nil {
 		return nil, err
 	}
@@ -96,7 +96,7 @@ func LookupFileId(server string, fileId string, readonly bool) (fullUrl string,
 	} else {
 		u = lookup.Locations.Head().Url
 	}
-	return "http://" + u + "/" + fileId, nil
+	return util.MkUrl(u, "/"+fileId, nil), nil
 }
 
 // LookupVolumeIds find volume locations by cache and actual lookup
@@ -123,7 +123,7 @@ func LookupVolumeIds(server string, vids []string) (map[string]LookupResult, err
 	for _, vid := range unknown_vids {
 		values.Add("volumeId", vid)
 	}
-	jsonBlob, err := util.Post("http://"+server+"/vol/lookup", values)
+	jsonBlob, err := util.Post(server, "/vol/lookup", values)
 	if err != nil {
 		return nil, err
 	}
diff --git a/go/operation/sync_volume.go b/go/operation/sync_volume.go
index 713cf33c1..f63d6f96a 100644
--- a/go/operation/sync_volume.go
+++ b/go/operation/sync_volume.go
@@ -20,7 +20,7 @@ type SyncVolumeResponse struct {
 func GetVolumeSyncStatus(server string, vid string) (*SyncVolumeResponse, error) {
 	values := make(url.Values)
 	values.Add("volume", vid)
-	jsonBlob, err := util.Post("http://"+server+"/admin/sync/status", values)
+	jsonBlob, err := util.Post(server, "/admin/sync/status", values)
 	glog.V(2).Info("sync volume result :", string(jsonBlob))
 	if err != nil {
 		return nil, err
diff --git a/go/storage/store.go b/go/storage/store.go
index 434c81b0a..702db99fa 100644
--- a/go/storage/store.go
+++ b/go/storage/store.go
@@ -316,7 +316,7 @@ func (s *Store) SendHeartbeatToMaster() (masterNode string, secretKey security.S
 		return "", "", err
 	}
 
-	joinUrl := "http://" + masterNode + "/dir/join"
+	joinUrl := util.MkUrl(masterNode, "/dir/join", nil)
 	glog.V(4).Infof("Connecting to %s ...", joinUrl)
 
 	jsonBlob, err := util.PostBytes(joinUrl, data)
diff --git a/go/storage/store_task.go b/go/storage/store_task.go
index 2f8c0515f..123b12f5f 100644
--- a/go/storage/store_task.go
+++ b/go/storage/store_task.go
@@ -4,12 +4,16 @@ import (
 	"errors"
 	"net/url"
 	"time"
+
+	"github.com/chrislusf/seaweedfs/go/glog"
 )
 
+type TaskType string
+
 const (
-	TaskVacuum  = "VACUUM"
-	TaskReplica = "REPLICA"
-	TaskBalance = "BALANCE"
+	TaskVacuum  TaskType = "VACUUM"
+	TaskReplica TaskType = "REPLICA"
+	TaskBalance TaskType = "BALANCE"
 )
 
 var (
@@ -27,18 +31,21 @@ type TaskWorker interface {
 }
 
 type Task struct {
-	startTime time.Time
-	worker    TaskWorker
-	ch        chan bool
-	result    error
+	Id              string
+	startTime       time.Time
+	worker          TaskWorker
+	ch              chan bool
+	result          error
+	cleanWhenFinish bool
 }
 
 type TaskManager struct {
 	TaskList map[string]*Task
 }
 
-func NewTask(worker TaskWorker) *Task {
+func NewTask(worker TaskWorker, id string) *Task {
 	t := &Task{
+		Id:        id,
 		worker:    worker,
 		startTime: time.Now(),
 		result:    ErrTaskNotFinish,
@@ -46,7 +53,12 @@ func NewTask(worker TaskWorker) *Task {
 	}
 	go func(t *Task) {
 		t.result = t.worker.Run()
+		if t.cleanWhenFinish {
+			glog.V(0).Infof("clean task (%s) when finish.", t.Id)
+			t.worker.Clean()
+		}
 		t.ch <- true
+
 	}(t)
 	return t
 }
@@ -75,7 +87,7 @@ func (tm *TaskManager) NewTask(s *Store, args url.Values) (tid string, e error)
 		return tid, ErrTaskExists
 	}
 	var tw TaskWorker
-	switch tt {
+	switch TaskType(tt) {
 	case TaskVacuum:
 		tw, e = NewVacuumTask(s, args)
 	case TaskReplica:
@@ -88,7 +100,7 @@ func (tm *TaskManager) NewTask(s *Store, args url.Values) (tid string, e error)
 	if tw == nil {
 		return "", ErrTaskInvalid
 	}
-	tm.TaskList[tid] = NewTask(tw)
+	tm.TaskList[tid] = NewTask(tw, tid)
 	return tid, nil
 }
 
@@ -112,16 +124,19 @@ func (tm *TaskManager) Commit(tid string) (e error) {
 	return t.worker.Commit()
 }
 
-func (tm *TaskManager) Clean(tid string) (e error) {
+func (tm *TaskManager) Clean(tid string) error {
 	t, ok := tm.TaskList[tid]
 	if !ok {
 		return ErrTaskNotFound
 	}
+	delete(tm.TaskList, tid)
 	if t.QueryResult(time.Second*30) == ErrTaskNotFinish {
-		return ErrTaskNotFinish
+		t.cleanWhenFinish = true
+		glog.V(0).Infof("task (%s) is not finish, clean it later.", tid)
+	} else {
+		t.worker.Clean()
 	}
-	delete(tm.TaskList, tid)
-	return t.worker.Clean()
+	return nil
 }
 
 func (tm *TaskManager) ElapsedDuration(tid string) (time.Duration, error) {
diff --git a/go/storage/store_task_cli.go b/go/storage/store_task_cli.go
new file mode 100644
index 000000000..fb69fed39
--- /dev/null
+++ b/go/storage/store_task_cli.go
@@ -0,0 +1,69 @@
+package storage
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+	"time"
+
+	"github.com/chrislusf/seaweedfs/go/util"
+)
+
+type TaskParams map[string]string
+
+var (
+	ErrTaskTimeout = errors.New("TaskTimeout")
+)
+
+type TaskCli struct {
+	TID      string
+	DataNode string
+}
+
+func NewTaskCli(dataNode string, task TaskType, params TaskParams) (*TaskCli, error) {
+	args := url.Values{}
+	args.Set("task", string(task))
+	for k, v := range params {
+		args.Set(k, v)
+	}
+	m, e := util.RemoteApiCall(dataNode, "/admin/task/new", args)
+	if e != nil {
+		return nil, e
+	}
+	tid := m["tid"].(string)
+	if tid == "" {
+		return nil, fmt.Errorf("Empty %s task", task)
+	}
+	return &TaskCli{
+		TID:      tid,
+		DataNode: dataNode,
+	}, nil
+}
+
+func (c *TaskCli) WaitAndQueryResult(timeout time.Duration) error {
+	startTime := time.Now()
+	args := url.Values{}
+	args.Set("task", c.TID)
+	for time.Since(startTime) < timeout {
+		_, e := util.RemoteApiCall(c.DataNode, "/admin/task/query", args)
+		if e.Error() == ErrTaskNotFinish.Error() {
+			continue
+		}
+		return e
+	}
+	return ErrTaskTimeout
+}
+
+func (c *TaskCli) Commit() error {
+	args := url.Values{}
+	args.Set("task", c.TID)
+	_, e := util.RemoteApiCall(c.DataNode, "/admin/task/commit", args)
+	return e
+}
+
+func (c *TaskCli) Clean() error {
+	args := url.Values{}
+	args.Set("task", c.TID)
+	_, e := util.RemoteApiCall(c.DataNode, "/admin/task/clean", args)
+	return e
+}
diff --git a/go/storage/store_task_replication.go b/go/storage/store_task_replication.go
index b6b8e230a..0931c831e 100644
--- a/go/storage/store_task_replication.go
+++ b/go/storage/store_task_replication.go
@@ -61,7 +61,7 @@ func (t *ReplicaTask) Run() error {
 		}
 		ch <- e
 	}()
-	errs := make([]error, 0, 2)
+	errs := make([]error, 0)
 	for i := 0; i < 2; i++ {
 		if e := <-ch; e != nil {
 			errs = append(errs, e)
diff --git a/go/topology/allocate_volume.go b/go/topology/allocate_volume.go
index 6de3130b1..e48f01495 100644
--- a/go/topology/allocate_volume.go
+++ b/go/topology/allocate_volume.go
@@ -19,7 +19,7 @@ func AllocateVolume(dn *DataNode, vid storage.VolumeId, option *VolumeGrowOption
 	values.Add("volume", vid.String())
 	values.Add("collection", option.Collection)
 	values.Add("ttl", option.Ttl.String())
-	jsonBlob, err := util.Post("http://"+dn.Url()+"/admin/assign_volume", values)
+	jsonBlob, err := util.Post(dn.Url(), "/admin/assign_volume", values)
 	if err != nil {
 		return err
 	}
diff --git a/go/topology/topology_replicate.go b/go/topology/topology_replicate.go
index dbb7d490a..9346ca743 100644
--- a/go/topology/topology_replicate.go
+++ b/go/topology/topology_replicate.go
@@ -6,7 +6,7 @@ func (t *Topology) Replicate() int {
 	glog.V(0).Infoln("Start replicate checker on demand")
 	for _, col := range t.collectionMap.Items {
 		c := col.(*Collection)
-		glog.V(0).Infoln("replicate on collection:", c.Name)
+		glog.V(0).Infoln("checking replicate on collection:", c.Name)
 		for _, vl := range c.storageType2VolumeLayout.Items {
 			if vl != nil {
 				volumeLayout := vl.(*VolumeLayout)
diff --git a/go/topology/topology_vacuum.go b/go/topology/topology_vacuum.go
index cba3e8a16..cd85f3b15 100644
--- a/go/topology/topology_vacuum.go
+++ b/go/topology/topology_vacuum.go
@@ -110,7 +110,7 @@ func vacuumVolume_Check(urlLocation string, vid storage.VolumeId, garbageThresho
 	values := make(url.Values)
 	values.Add("volume", vid.String())
 	values.Add("garbageThreshold", garbageThreshold)
-	jsonBlob, err := util.Post("http://"+urlLocation+"/admin/vacuum/check", values)
+	jsonBlob, err := util.Post(urlLocation, "/admin/vacuum/check", values)
 	if err != nil {
 		glog.V(0).Infoln("parameters:", values)
 		return err, false
@@ -127,7 +127,7 @@ func vacuumVolume_Check(urlLocation string, vid storage.VolumeId, garbageThresho
 func vacuumVolume_Compact(urlLocation string, vid storage.VolumeId) error {
 	values := make(url.Values)
 	values.Add("volume", vid.String())
-	jsonBlob, err := util.Post("http://"+urlLocation+"/admin/vacuum/compact", values)
+	jsonBlob, err := util.Post(urlLocation, "/admin/vacuum/compact", values)
 	if err != nil {
 		return err
 	}
@@ -143,7 +143,7 @@ func vacuumVolume_Compact(urlLocation string, vid storage.VolumeId) error {
 func vacuumVolume_Commit(urlLocation string, vid storage.VolumeId) error {
 	values := make(url.Values)
 	values.Add("volume", vid.String())
-	jsonBlob, err := util.Post("http://"+urlLocation+"/admin/vacuum/commit", values)
+	jsonBlob, err := util.Post(urlLocation, "/admin/vacuum/commit", values)
 	if err != nil {
 		return err
 	}
diff --git a/go/util/http_util.go b/go/util/http_util.go
index 5060c77ad..65a4d21df 100644
--- a/go/util/http_util.go
+++ b/go/util/http_util.go
@@ -28,6 +28,18 @@ func init() {
 	client = &http.Client{Transport: Transport}
 }
 
+func MkUrl(host, path string, args url.Values) string {
+	u := url.URL{
+		Scheme: "http",
+		Host:   host,
+		Path:   path,
+	}
+	if args != nil {
+		u.RawQuery = args.Encode()
+	}
+	return u.String()
+}
+
 func PostBytes(url string, body []byte) ([]byte, error) {
 	r, err := client.Post(url, "application/octet-stream", bytes.NewReader(body))
 	if err != nil {
@@ -41,20 +53,45 @@ func PostBytes(url string, body []byte) ([]byte, error) {
 	return b, nil
 }
 
-func Post(url string, values url.Values) ([]byte, error) {
+func PostEx(host, path string, values url.Values) (content []byte, statusCode int, e error) {
+	url := MkUrl(host, path, nil)
 	r, err := client.PostForm(url, values)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 	defer r.Body.Close()
 	b, err := ioutil.ReadAll(r.Body)
 	if err != nil {
-		return nil, err
+		return nil, r.StatusCode, err
 	}
-	return b, nil
+	return b, r.StatusCode, nil
+}
+
+func Post(host, path string, values url.Values) (content []byte, e error) {
+	content, _, e = PostEx(host, path, values)
+	return
+}
+
+func RemoteApiCall(host, path string, values url.Values) (result map[string]interface{}, e error) {
+	jsonBlob, code, e := PostEx(host, path, values)
+	if e != nil {
+		return nil, e
+	}
+	result = make(map[string]interface{})
+	if e := json.Unmarshal(jsonBlob, result); e != nil {
+		return nil, e
+	}
+	if err, ok := result["error"]; ok && err.(string) != "" {
+		return nil, errors.New(err.(string))
+	}
+	if code != http.StatusOK {
+		return nil, fmt.Errorf("RemoteApiCall %s/%s return %d", host, path, code)
+	}
+	return result, nil
 }
 
-func Get(url string) ([]byte, error) {
+func Get(host, path string, values url.Values) ([]byte, error) {
+	url := MkUrl(host, path, values)
 	r, err := client.Get(url)
 	if err != nil {
 		return nil, err
diff --git a/go/util/url_util.go b/go/util/url_util.go
deleted file mode 100644
index 7204d08b0..000000000
--- a/go/util/url_util.go
+++ /dev/null
@@ -1,13 +0,0 @@
-package util
-
-import "net/url"
-
-func MkUrl(host, path string, args url.Values) string {
-	u := url.URL{
-		Scheme: "http",
-		Host:   host,
-		Path:   path,
-	}
-	u.RawQuery = args.Encode()
-	return u.String()
-}
diff --git a/go/weed/benchmark.go b/go/weed/benchmark.go
index 51652b1ae..daa970788 100644
--- a/go/weed/benchmark.go
+++ b/go/weed/benchmark.go
@@ -255,14 +255,13 @@ func readFiles(fileIdLineChan chan string, s *stat) {
 			continue
 		}
 		server := ret.Locations.PickForRead().Url
-		url := "http://" + server + "/" + fid
-		if bytesRead, err := util.Get(url); err == nil {
+		if bytesRead, err := util.Get(server, "/"+fid, nil); err == nil {
 			s.completed++
 			s.transferred += int64(len(bytesRead))
 			readStats.addSample(time.Now().Sub(start))
 		} else {
 			s.failed++
-			fmt.Printf("Failed to read %s error:%v\n", url, err)
+			fmt.Printf("Failed to read %s/%s error:%v\n", server, fid, err)
 		}
 	}
 }
diff --git a/go/weed/weed_server/master_server_handlers_admin.go b/go/weed/weed_server/master_server_handlers_admin.go
index 89c373ec7..4b7f809ec 100644
--- a/go/weed/weed_server/master_server_handlers_admin.go
+++ b/go/weed/weed_server/master_server_handlers_admin.go
@@ -28,7 +28,7 @@ func (ms *MasterServer) collectionDeleteHandler(w http.ResponseWriter, r *http.R
 		return
 	}
 	for _, server := range collection.ListVolumeServers() {
-		_, err := util.Get("http://" + server.Ip + ":" + strconv.Itoa(server.Port) + "/admin/delete_collection?collection=" + r.FormValue("collection"))
+		_, err := util.Get(server.Ip+":"+strconv.Itoa(server.Port), "/admin/delete_collection", url.Values{"collection": r.Form["collection"]})
 		if err != nil {
 			writeJsonError(w, r, http.StatusInternalServerError, err)
 			return
@@ -204,7 +204,7 @@ func (ms *MasterServer) batchSetVolumeOption(settingKey, settingValue string, vo
 		wg.Add(1)
 		go func(server string, values url.Values) {
 			defer wg.Done()
-			jsonBlob, e := util.Post("http://"+server+"/admin/setting", values)
+			jsonBlob, e := util.Post(server, "/admin/setting", values)
 			if e != nil {
 				result[server] = map[string]interface{}{
 					"error": e.Error() + " " + string(jsonBlob),