diff --git a/go.mod b/go.mod
index e6645e4a1..96ea8fd3d 100644
--- a/go.mod
+++ b/go.mod
@@ -7,6 +7,7 @@ require (
 	github.com/Azure/azure-pipeline-go v0.2.2 // indirect
 	github.com/Azure/azure-storage-blob-go v0.8.0
 	github.com/DataDog/zstd v1.4.1 // indirect
+	github.com/OneOfOne/xxhash v1.2.2
 	github.com/Shopify/sarama v1.23.1
 	github.com/aws/aws-sdk-go v1.23.13
 	github.com/chrislusf/raft v0.0.0-20190225081310-10d6e2182d92
@@ -24,7 +25,6 @@ require (
 	github.com/facebookgo/stats v0.0.0-20151006221625-1b76add642e4
 	github.com/facebookgo/subset v0.0.0-20200203212716-c811ad88dec4 // indirect
 	github.com/frankban/quicktest v1.7.2 // indirect
-	github.com/gabriel-vasile/mimetype v1.0.0
 	github.com/go-redis/redis v6.15.7+incompatible
 	github.com/go-sql-driver/mysql v1.4.1
 	github.com/gocql/gocql v0.0.0-20190829130954-e163eff7a8c6
diff --git a/go.sum b/go.sum
index 2c2f1012b..a382daf10 100644
--- a/go.sum
+++ b/go.sum
@@ -35,6 +35,7 @@ github.com/DataDog/zstd v1.3.6-0.20190409195224-796139022798/go.mod h1:1jcaCB/uf
 github.com/DataDog/zstd v1.4.1 h1:3oxKN3wbHibqx897utPC2LTQU4J+IHWWJO+glkAkpFM=
 github.com/DataDog/zstd v1.4.1/go.mod h1:1jcaCB/ufaK+sKp1NBhlGmpz41jOoPQ35bpF36t7BBo=
 github.com/GoogleCloudPlatform/cloudsql-proxy v0.0.0-20190605020000-c4ba1fdf4d36/go.mod h1:aJ4qN3TfrelA6NZ6AXsXRfmEVaYin3EDbSPJrKS8OXo=
+github.com/OneOfOne/xxhash v1.2.2 h1:KMrpdQIwFcEqXDklaen+P1axHaj9BSKzvpUUfnHldSE=
 github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
 github.com/Shopify/sarama v1.23.1 h1:XxJBCZEoWJtoWjf/xRbmGUpAmTZGnuuF0ON0EvxxBrs=
 github.com/Shopify/sarama v1.23.1/go.mod h1:XLH1GYJnLVE0XCr6KdJGVJRTwY30moWNJ4sERjXX6fs=
@@ -61,6 +62,7 @@ github.com/census-instrumentation/opencensus-proto v0.2.0 h1:LzQXZOgg4CQfE6bFvXG
 github.com/census-instrumentation/opencensus-proto v0.2.0/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/census-instrumentation/opencensus-proto v0.2.1 h1:glEXhBS5PSLLv4IXzLA5yPRVX4bilULVyxxbrfOtDAk=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
+github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/chrislusf/raft v0.0.0-20190225081310-10d6e2182d92 h1:lM9SFsh0EPXkyJyrTJqLZPAIJBtNFP6LNkYXu2MnSZI=
 github.com/chrislusf/raft v0.0.0-20190225081310-10d6e2182d92/go.mod h1:4jyiUCD5y548+yKW+oiHtccBiMaLCCbFBpK2t7X4eUo=
@@ -91,8 +93,6 @@ github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumC
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8PWV+bWy6jNmig1y/TA+kYO4g3RSRF0IAv0no=
 github.com/dimchansky/utfbom v1.1.0/go.mod h1:rO41eb7gLfo8SF1jd9F8HplJm1Fewwi4mQvIirEdv+8=
-github.com/disintegration/imaging v1.6.1 h1:JnBbK6ECIZb1NsWIikP9pd8gIlTIRx7fuDNpU9fsxOE=
-github.com/disintegration/imaging v1.6.1/go.mod h1:xuIt+sRxDFrHS0drzXUlCJthkJ8k7lkkUojDSR247MQ=
 github.com/disintegration/imaging v1.6.2 h1:w1LecBlG2Lnp8B3jk5zSuNqd7b4DXhcjwek1ei82L+c=
 github.com/disintegration/imaging v1.6.2/go.mod h1:44/5580QXChDfwIclfc/PCwrr44amcmDAg8hxG0Ewe4=
 github.com/dustin/go-humanize v1.0.0 h1:VSnTsYCnlFHaM2/igO1h6X3HA71jcobQuxemgkq4zYo=
@@ -124,8 +124,6 @@ github.com/frankban/quicktest v1.7.2 h1:2QxQoC1TS09S7fhCPsrvqYdvP1H5M1P1ih5ABm3B
 github.com/frankban/quicktest v1.7.2/go.mod h1:jaStnuzAqU1AJdCO0l53JDCJrVDKcS03DbaAcR7Ks/o=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
-github.com/gabriel-vasile/mimetype v1.0.0 h1:0QKnAQQhG6oOsb4GK7iPlet7RtjHi9us8RF/nXoTxhI=
-github.com/gabriel-vasile/mimetype v1.0.0/go.mod h1:6CDPel/o/3/s4+bp6kIbsWATq8pmgOisOPG40CJa6To=
 github.com/ghodss/yaml v1.0.0 h1:wQHKEahhL6wmXdzwWG11gIVCkOv05bNOh+Rxn0yngAk=
 github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
 github.com/go-ini/ini v1.25.4/go.mod h1:ByCAeIL28uOIIG0E3PJtZPDL8WnHpFKFOtgjp+3Ies8=
@@ -246,8 +244,6 @@ github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T
 github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
-github.com/jacobsa/daemonize v0.0.0-20160101105449-e460293e890f h1:X+tnaqoCcBgAwSTJtoYW6p0qKiuPyMfofEHEFUf2kdU=
-github.com/jacobsa/daemonize v0.0.0-20160101105449-e460293e890f/go.mod h1:Ip4fOwzCrnDVuluHBd7FXIMb7SHOKfkt9/UDrYSZvqI=
 github.com/jcmturner/gofork v0.0.0-20190328161633-dc7c13fece03 h1:FUwcHNlEqkqLjLBdCp5PRlCFijNjvcYANOZXzCfXwCM=
 github.com/jcmturner/gofork v0.0.0-20190328161633-dc7c13fece03/go.mod h1:MK8+TM0La+2rjBD4jE12Kj1pCCxK7d2LK/UM3ncEo0o=
 github.com/jcmturner/gofork v1.0.0 h1:J7uCkflzTEhUZ64xqKnkDxq3kzc96ajM1Gli5ktUem8=
@@ -389,8 +385,6 @@ github.com/prometheus/procfs v0.0.3/go.mod h1:4A/X28fw3Fc593LaREMrKMqOKvUAntwMDa
 github.com/prometheus/procfs v0.0.4 h1:w8DjqFMJDjuVwdZBQoOozr4MVWOnwF7RcL/7uxBjY78=
 github.com/prometheus/procfs v0.0.4/go.mod h1:4A/X28fw3Fc593LaREMrKMqOKvUAntwMDaekg4FpcdQ=
 github.com/prometheus/tsdb v0.7.1/go.mod h1:qhTCs0VvXwvX/y3TZrWD7rabWM+ijKTux40TwIPHuXU=
-github.com/rakyll/statik v0.1.6 h1:uICcfUXpgqtw2VopbIncslhAmE5hwc4g20TEyEENBNs=
-github.com/rakyll/statik v0.1.6/go.mod h1:OEi9wJV/fMUAGx1eNjq75DKDsJVuEv1U0oYdX6GX8Zs=
 github.com/rakyll/statik v0.1.7 h1:OF3QCZUuyPxuGEP7B4ypUa7sB/iHtqOTDYZXGM8KOdQ=
 github.com/rakyll/statik v0.1.7/go.mod h1:AlZONWzMtEnMs7W4e/1LURLiI49pIMmp6V9Unghqrcc=
 github.com/rcrowley/go-metrics v0.0.0-20181016184325-3113b8401b8a h1:9ZKAASQSHhDYGoxY8uLVpewe1GDZ2vu2Tr/vTdVAkFQ=
@@ -401,8 +395,6 @@ github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6So
 github.com/rogpeppe/go-internal v1.1.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/rogpeppe/go-internal v1.2.2/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
-github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd h1:CmH9+J6ZSsIjUK3dcGsnCnO41eRBOnY12zwkn5qVwgc=
-github.com/rwcarlsen/goexif v0.0.0-20190401172101-9e8deecbddbd/go.mod h1:hPqNNc0+uJM6H+SuU8sEs5K5IQeKccPqeSjfgcKGgPk=
 github.com/seaweedfs/fuse v0.0.0-20190510212405-310228904eff h1:uLd5zBvf5OA67wcVRePHrFt60bR4LSskaVhgVwyk0Jg=
 github.com/seaweedfs/fuse v0.0.0-20190510212405-310228904eff/go.mod h1:cubdLmQFqEUZ9vNJrznhgc3m3VMAJi/nY2Ix2axXkG0=
 github.com/seaweedfs/goexif v1.0.2 h1:p+rTXYdQ2mgxd+1JaTrQ9N8DvYuw9UH9xgYmJ+Bb29E=
@@ -510,11 +502,8 @@ golang.org/x/crypto v0.0.0-20190911031432-227b76d455e7 h1:0hQKqeLdqlt5iIwVOBErRi
 golang.org/x/crypto v0.0.0-20190911031432-227b76d455e7/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
-golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81/go.mod h1:ux5Hcp/YLpHSI86hEcLt0YII63i6oz57MZXIpbrjZUs=
 golang.org/x/image v0.0.0-20190227222117-0694c2d4d067 h1:KYGJGHOQy8oSi1fDlSpcZF0+juKwk/hEMv5SiwHogR0=
 golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
-golang.org/x/image v0.0.0-20190829233526-b3c06291d021 h1:j6QOxNFMpEL1wIQX6TUdBPNfGZKmBOJS/vfSm8a7tdM=
-golang.org/x/image v0.0.0-20190829233526-b3c06291d021/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/image v0.0.0-20200119044424-58c23975cae1 h1:5h3ngYt7+vXCDZCup/HkCQgW5XwmSvR/nA2JmJ0RErg=
 golang.org/x/image v0.0.0-20200119044424-58c23975cae1/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
diff --git a/weed/command/filer_copy.go b/weed/command/filer_copy.go
index 0e9e10ee3..b6ac7854b 100644
--- a/weed/command/filer_copy.go
+++ b/weed/command/filer_copy.go
@@ -14,6 +14,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"google.golang.org/grpc"
 
 	"github.com/chrislusf/seaweedfs/weed/operation"
@@ -134,7 +135,7 @@ func runCopy(cmd *Command, args []string) bool {
 	copy.ttlSec = int32(ttl.Minutes()) * 60
 
 	if *cmdCopy.IsDebug {
-		util.SetupProfiling("filer.copy.cpu.pprof", "filer.copy.mem.pprof")
+		grace.SetupProfiling("filer.copy.cpu.pprof", "filer.copy.mem.pprof")
 	}
 
 	fileCopyTaskChan := make(chan FileCopyTask, *copy.concurrenctFiles)
diff --git a/weed/command/master.go b/weed/command/master.go
index 7e69f558c..6301c7730 100644
--- a/weed/command/master.go
+++ b/weed/command/master.go
@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/chrislusf/raft/protobuf"
+	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"github.com/gorilla/mux"
 	"google.golang.org/grpc/reflection"
 
@@ -82,7 +83,7 @@ func runMaster(cmd *Command, args []string) bool {
 	util.LoadConfiguration("master", false)
 
 	runtime.GOMAXPROCS(runtime.NumCPU())
-	util.SetupProfiling(*masterCpuProfile, *masterMemProfile)
+	grace.SetupProfiling(*masterCpuProfile, *masterMemProfile)
 
 	if err := util.TestFolderWritable(*m.metaFolder); err != nil {
 		glog.Fatalf("Check Meta Folder (-mdir) Writable %s : %s", *m.metaFolder, err)
diff --git a/weed/command/mount_std.go b/weed/command/mount_std.go
index b1e47809c..2dc9aa196 100644
--- a/weed/command/mount_std.go
+++ b/weed/command/mount_std.go
@@ -19,13 +19,14 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
 	"github.com/chrislusf/seaweedfs/weed/security"
 	"github.com/chrislusf/seaweedfs/weed/util"
+	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"github.com/seaweedfs/fuse"
 	"github.com/seaweedfs/fuse/fs"
 )
 
 func runMount(cmd *Command, args []string) bool {
 
-	util.SetupProfiling(*mountCpuProfile, *mountMemProfile)
+	grace.SetupProfiling(*mountCpuProfile, *mountMemProfile)
 
 	umask, umaskErr := strconv.ParseUint(*mountOptions.umaskString, 8, 64)
 	if umaskErr != nil {
@@ -144,7 +145,7 @@ func RunMount(option *MountOptions, umask os.FileMode) bool {
 	}
 	defer fuse.Unmount(dir)
 
-	util.OnInterrupt(func() {
+	grace.OnInterrupt(func() {
 		fuse.Unmount(dir)
 		c.Close()
 	})
diff --git a/weed/command/msg_broker.go b/weed/command/msg_broker.go
index d4d3865fa..984497c2e 100644
--- a/weed/command/msg_broker.go
+++ b/weed/command/msg_broker.go
@@ -6,6 +6,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"google.golang.org/grpc/reflection"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
@@ -57,7 +58,7 @@ func runMsgBroker(cmd *Command, args []string) bool {
 
 func (msgBrokerOpt *QueueOptions) startQueueServer() bool {
 
-	util.SetupProfiling(*messageBrokerStandaloneOptions.cpuprofile, *messageBrokerStandaloneOptions.memprofile)
+	grace.SetupProfiling(*messageBrokerStandaloneOptions.cpuprofile, *messageBrokerStandaloneOptions.memprofile)
 
 	filerGrpcAddress, err := pb.ParseFilerGrpcAddress(*msgBrokerOpt.filer)
 	if err != nil {
diff --git a/weed/command/volume.go b/weed/command/volume.go
index eab24ca97..6258be6cf 100644
--- a/weed/command/volume.go
+++ b/weed/command/volume.go
@@ -10,6 +10,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"github.com/spf13/viper"
 	"google.golang.org/grpc"
 
@@ -93,7 +94,7 @@ func runVolume(cmd *Command, args []string) bool {
 	util.LoadConfiguration("security", false)
 
 	runtime.GOMAXPROCS(runtime.NumCPU())
-	util.SetupProfiling(*v.cpuProfile, *v.memProfile)
+	grace.SetupProfiling(*v.cpuProfile, *v.memProfile)
 
 	v.startVolumeServer(*volumeFolders, *maxVolumeCounts, *volumeWhiteListOption)
 
@@ -183,7 +184,7 @@ func (v VolumeServerOptions) startVolumeServer(volumeFolders, maxVolumeCounts, v
 	clusterHttpServer := v.startClusterHttpService(volumeMux)
 
 	stopChain := make(chan struct{})
-	util.OnInterrupt(func() {
+	grace.OnInterrupt(func() {
 		fmt.Println("volume server has be killed")
 		var startTime time.Time
 
diff --git a/weed/filesys/wfs.go b/weed/filesys/wfs.go
index e7d1766b6..33403aaf8 100644
--- a/weed/filesys/wfs.go
+++ b/weed/filesys/wfs.go
@@ -10,6 +10,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"github.com/karlseguin/ccache"
 	"google.golang.org/grpc"
 
@@ -89,18 +90,18 @@ func NewSeaweedFileSystem(option *Option) *WFS {
 	}
 	if option.CacheSizeMB > 0 {
 		wfs.chunkCache = chunk_cache.NewChunkCache(256, option.CacheDir, option.CacheSizeMB)
-		util.OnInterrupt(func() {
+		grace.OnInterrupt(func() {
 			wfs.chunkCache.Shutdown()
 		})
 	}
 	if wfs.option.AsyncMetaDataCaching {
 		wfs.metaCache = meta_cache.NewMetaCache(path.Join(option.CacheDir, "meta"))
 		startTime := time.Now()
-		if err := meta_cache.InitMetaCache(wfs.metaCache, wfs, wfs.option.FilerMountRootPath); err != nil{
+		if err := meta_cache.InitMetaCache(wfs.metaCache, wfs, wfs.option.FilerMountRootPath); err != nil {
 			glog.V(0).Infof("failed to init meta cache: %v", err)
 		} else {
 			go meta_cache.SubscribeMetaEvents(wfs.metaCache, wfs, wfs.option.FilerMountRootPath, startTime.UnixNano())
-			util.OnInterrupt(func() {
+			grace.OnInterrupt(func() {
 				wfs.metaCache.Shutdown()
 			})
 		}
diff --git a/weed/server/filer_server.go b/weed/server/filer_server.go
index 596c91a58..956684d46 100644
--- a/weed/server/filer_server.go
+++ b/weed/server/filer_server.go
@@ -8,6 +8,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"google.golang.org/grpc"
 
 	"github.com/chrislusf/seaweedfs/weed/operation"
@@ -111,7 +112,7 @@ func NewFilerServer(defaultMux, readonlyMux *http.ServeMux, option *FilerOption)
 
 	fs.filer.LoadBuckets()
 
-	util.OnInterrupt(func() {
+	grace.OnInterrupt(func() {
 		fs.filer.Shutdown()
 	})
 
diff --git a/weed/server/webdav_server.go b/weed/server/webdav_server.go
index 445cc7b4d..11b89677f 100644
--- a/weed/server/webdav_server.go
+++ b/weed/server/webdav_server.go
@@ -10,6 +10,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/chrislusf/seaweedfs/weed/util/grace"
 	"golang.org/x/net/webdav"
 	"google.golang.org/grpc"
 
@@ -100,7 +101,7 @@ type WebDavFile struct {
 func NewWebDavFileSystem(option *WebDavOption) (webdav.FileSystem, error) {
 
 	chunkCache := chunk_cache.NewChunkCache(256, option.CacheDir, option.CacheSizeMB)
-	util.OnInterrupt(func() {
+	grace.OnInterrupt(func() {
 		chunkCache.Shutdown()
 	})
 	return &WebDavFileSystem{
diff --git a/weed/util/pprof.go b/weed/util/grace/pprof.go
similarity index 97%
rename from weed/util/pprof.go
rename to weed/util/grace/pprof.go
index a2621ceee..14686bfc8 100644
--- a/weed/util/pprof.go
+++ b/weed/util/grace/pprof.go
@@ -1,4 +1,4 @@
-package util
+package grace
 
 import (
 	"os"
diff --git a/weed/util/signal_handling.go b/weed/util/grace/signal_handling.go
similarity index 98%
rename from weed/util/signal_handling.go
rename to weed/util/grace/signal_handling.go
index 99447e8be..7cca46764 100644
--- a/weed/util/signal_handling.go
+++ b/weed/util/grace/signal_handling.go
@@ -1,6 +1,6 @@
 // +build !plan9
 
-package util
+package grace
 
 import (
 	"os"
diff --git a/weed/util/signal_handling_notsupported.go b/weed/util/grace/signal_handling_notsupported.go
similarity index 78%
rename from weed/util/signal_handling_notsupported.go
rename to weed/util/grace/signal_handling_notsupported.go
index c389cfb7e..5335915a1 100644
--- a/weed/util/signal_handling_notsupported.go
+++ b/weed/util/grace/signal_handling_notsupported.go
@@ -1,6 +1,6 @@
 // +build plan9
 
-package util
+package grace
 
 func OnInterrupt(fn func()) {
 }