diff --git a/weed/storage/volume_loading.go b/weed/storage/volume_loading.go
index 42780341b..5c1ac172a 100644
--- a/weed/storage/volume_loading.go
+++ b/weed/storage/volume_loading.go
@@ -13,16 +13,15 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 )
 
-func loadVolumeWithoutIndex(dirname string, collection string, id needle.VolumeId, needleMapKind NeedleMapType) (v *Volume, e error) {
+func loadVolumeWithoutIndex(dirname string, collection string, id needle.VolumeId, needleMapKind NeedleMapType) (v *Volume, err error) {
 	v = &Volume{dir: dirname, Collection: collection, Id: id}
 	v.SuperBlock = SuperBlock{}
 	v.needleMapKind = needleMapKind
-	e = v.load(false, false, needleMapKind, 0)
+	err = v.load(false, false, needleMapKind, 0)
 	return
 }
 
-func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind NeedleMapType, preallocate int64) error {
-	var e error
+func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind NeedleMapType, preallocate int64) (err error) {
 	fileName := v.FileName()
 	alreadyHasSuperBlock := false
 
@@ -37,10 +36,10 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 		}
 		var dataFile *os.File
 		if canWrite {
-			dataFile, e = os.OpenFile(fileName+".dat", os.O_RDWR|os.O_CREATE, 0644)
+			dataFile, err = os.OpenFile(fileName+".dat", os.O_RDWR|os.O_CREATE, 0644)
 		} else {
 			glog.V(0).Infoln("opening " + fileName + ".dat in READONLY mode")
-			dataFile, e = os.Open(fileName + ".dat")
+			dataFile, err = os.Open(fileName + ".dat")
 			v.noWriteOrDelete = true
 		}
 		v.lastModifiedTsSeconds = uint64(modifiedTime.Unix())
@@ -50,56 +49,56 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 		v.DataBackend = backend.NewDiskFile(dataFile)
 	} else {
 		if createDatIfMissing {
-			v.DataBackend, e = createVolumeFile(fileName+".dat", preallocate, v.MemoryMapMaxSizeMb)
+			v.DataBackend, err = createVolumeFile(fileName+".dat", preallocate, v.MemoryMapMaxSizeMb)
 		} else {
 			return fmt.Errorf("Volume Data file %s.dat does not exist.", fileName)
 		}
 	}
 
-	if e != nil {
-		if !os.IsPermission(e) {
-			return fmt.Errorf("cannot load Volume Data %s.dat: %v", fileName, e)
+	if err != nil {
+		if !os.IsPermission(err) {
+			return fmt.Errorf("cannot load Volume Data %s.dat: %v", fileName, err)
 		} else {
-			return fmt.Errorf("load data file %s.dat: %v", fileName, e)
+			return fmt.Errorf("load data file %s.dat: %v", fileName, err)
 		}
 	}
 
 	if alreadyHasSuperBlock {
-		e = v.readSuperBlock()
+		err = v.readSuperBlock()
 	} else {
 		if !v.SuperBlock.Initialized() {
 			return fmt.Errorf("volume %s.dat not initialized", fileName)
 		}
-		e = v.maybeWriteSuperBlock()
+		err = v.maybeWriteSuperBlock()
 	}
-	if e == nil && alsoLoadIndex {
+	if err == nil && alsoLoadIndex {
 		var indexFile *os.File
 		if v.noWriteOrDelete {
 			glog.V(1).Infoln("open to read file", fileName+".idx")
-			if indexFile, e = os.OpenFile(fileName+".idx", os.O_RDONLY, 0644); e != nil {
-				return fmt.Errorf("cannot read Volume Index %s.idx: %v", fileName, e)
+			if indexFile, err = os.OpenFile(fileName+".idx", os.O_RDONLY, 0644); err != nil {
+				return fmt.Errorf("cannot read Volume Index %s.idx: %v", fileName, err)
 			}
 		} else {
 			glog.V(1).Infoln("open to write file", fileName+".idx")
-			if indexFile, e = os.OpenFile(fileName+".idx", os.O_RDWR|os.O_CREATE, 0644); e != nil {
-				return fmt.Errorf("cannot write Volume Index %s.idx: %v", fileName, e)
+			if indexFile, err = os.OpenFile(fileName+".idx", os.O_RDWR|os.O_CREATE, 0644); err != nil {
+				return fmt.Errorf("cannot write Volume Index %s.idx: %v", fileName, err)
 			}
 		}
-		if v.lastAppendAtNs, e = CheckVolumeDataIntegrity(v, indexFile); e != nil {
+		if v.lastAppendAtNs, err = CheckVolumeDataIntegrity(v, indexFile); err != nil {
 			v.noWriteOrDelete = true
-			glog.V(0).Infof("volumeDataIntegrityChecking failed %v", e)
+			glog.V(0).Infof("volumeDataIntegrityChecking failed %v", err)
 		}
 
 		if v.noWriteOrDelete || v.noWriteCanDelete {
-			if v.nm, e = NewSortedFileNeedleMap(fileName, indexFile); e != nil {
-				glog.V(0).Infof("loading sorted db %s error: %v", fileName+".sdb", e)
+			if v.nm, err = NewSortedFileNeedleMap(fileName, indexFile); err != nil {
+				glog.V(0).Infof("loading sorted db %s error: %v", fileName+".sdb", err)
 			}
 		} else {
 			switch needleMapKind {
 			case NeedleMapInMemory:
 				glog.V(0).Infoln("loading index", fileName+".idx", "to memory")
-				if v.nm, e = LoadCompactNeedleMap(indexFile); e != nil {
-					glog.V(0).Infof("loading index %s to memory error: %v", fileName+".idx", e)
+				if v.nm, err = LoadCompactNeedleMap(indexFile); err != nil {
+					glog.V(0).Infof("loading index %s to memory error: %v", fileName+".idx", err)
 				}
 			case NeedleMapLevelDb:
 				glog.V(0).Infoln("loading leveldb", fileName+".ldb")
@@ -108,8 +107,8 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 					WriteBuffer:                   1 * 1024 * 1024, // default value is 4MiB
 					CompactionTableSizeMultiplier: 10,              // default value is 1
 				}
-				if v.nm, e = NewLevelDbNeedleMap(fileName+".ldb", indexFile, opts); e != nil {
-					glog.V(0).Infof("loading leveldb %s error: %v", fileName+".ldb", e)
+				if v.nm, err = NewLevelDbNeedleMap(fileName+".ldb", indexFile, opts); err != nil {
+					glog.V(0).Infof("loading leveldb %s error: %v", fileName+".ldb", err)
 				}
 			case NeedleMapLevelDbMedium:
 				glog.V(0).Infoln("loading leveldb medium", fileName+".ldb")
@@ -118,8 +117,8 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 					WriteBuffer:                   2 * 1024 * 1024, // default value is 4MiB
 					CompactionTableSizeMultiplier: 10,              // default value is 1
 				}
-				if v.nm, e = NewLevelDbNeedleMap(fileName+".ldb", indexFile, opts); e != nil {
-					glog.V(0).Infof("loading leveldb %s error: %v", fileName+".ldb", e)
+				if v.nm, err = NewLevelDbNeedleMap(fileName+".ldb", indexFile, opts); err != nil {
+					glog.V(0).Infof("loading leveldb %s error: %v", fileName+".ldb", err)
 				}
 			case NeedleMapLevelDbLarge:
 				glog.V(0).Infoln("loading leveldb large", fileName+".ldb")
@@ -128,8 +127,8 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 					WriteBuffer:                   4 * 1024 * 1024, // default value is 4MiB
 					CompactionTableSizeMultiplier: 10,              // default value is 1
 				}
-				if v.nm, e = NewLevelDbNeedleMap(fileName+".ldb", indexFile, opts); e != nil {
-					glog.V(0).Infof("loading leveldb %s error: %v", fileName+".ldb", e)
+				if v.nm, err = NewLevelDbNeedleMap(fileName+".ldb", indexFile, opts); err != nil {
+					glog.V(0).Infof("loading leveldb %s error: %v", fileName+".ldb", err)
 				}
 			}
 		}
@@ -137,7 +136,7 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 
 	stats.VolumeServerVolumeCounter.WithLabelValues(v.Collection, "volume").Inc()
 
-	return e
+	return err
 }
 
 func checkFile(filename string) (exists, canRead, canWrite bool, modTime time.Time, fileSize int64) {