diff --git a/go/storage/collection_settings.go b/go/storage/collection_settings.go
index 5ea0d11b9..84653f054 100644
--- a/go/storage/collection_settings.go
+++ b/go/storage/collection_settings.go
@@ -43,11 +43,11 @@ func (cs *CollectionSettings) ToPbMessage() []*weedpb.CollectionSetting {
 		setting := &weedpb.CollectionSetting{
 			Collection: collection,
 		}
-		if v, ok := m[keyReplicatePlacement]; ok {
+		if v, ok := m[keyReplicatePlacement]; ok && v != nil {
 			setting.ReplicaPlacement = v.(*ReplicaPlacement).String()
 		}
-		if v, ok := m[keyGarbageThreshold]; ok {
-			setting.ReplicaPlacement = v.(string)
+		if v, ok := m[keyGarbageThreshold]; ok && v != nil {
+			setting.VacuumGarbageThreshold = v.(string)
 		}
 		msg = append(msg, setting)
 	}
@@ -87,7 +87,12 @@ func (cs *CollectionSettings) GetGarbageThreshold(collection string) string {
 }
 
 func (cs *CollectionSettings) SetGarbageThreshold(collection string, gt string) {
-	cs.set(collection, keyGarbageThreshold, gt)
+	if gt == "" {
+		cs.set(collection, keyGarbageThreshold, nil)
+	} else {
+		cs.set(collection, keyGarbageThreshold, gt)
+
+	}
 }
 
 func (cs *CollectionSettings) GetReplicaPlacement(collection string) *ReplicaPlacement {
@@ -100,6 +105,10 @@ func (cs *CollectionSettings) GetReplicaPlacement(collection string) *ReplicaPla
 }
 
 func (cs *CollectionSettings) SetReplicaPlacement(collection, t string) error {
+	if t == "" {
+		cs.set(collection, keyReplicatePlacement, nil)
+		return nil
+	}
 	rp, e := NewReplicaPlacementFromString(t)
 	if e == nil {
 		cs.set(collection, keyReplicatePlacement, rp)
diff --git a/go/storage/collection_settings_test.go b/go/storage/collection_settings_test.go
new file mode 100644
index 000000000..88e35f737
--- /dev/null
+++ b/go/storage/collection_settings_test.go
@@ -0,0 +1,32 @@
+package storage
+
+import (
+	"testing"
+	"reflect"
+	"encoding/json"
+)
+
+func TestCollectionSettings(t *testing.T) {
+	cs1 := NewCollectionSettings("000", "0.3")
+	cs1.SetReplicaPlacement("col1", "001")
+	cs1.SetGarbageThreshold("col2", "0.5")
+
+	if cs1.GetGarbageThreshold("col1") != "0.3" ||
+		cs1.GetGarbageThreshold("col2") != "0.5" ||
+		cs1.GetGarbageThreshold("") != "0.3" ||
+		cs1.GetReplicaPlacement("").String() != "000" ||
+		cs1.GetReplicaPlacement("col1").String() != "001" ||
+		cs1.GetReplicaPlacement("col2").String() != "000" {
+		t.Fatal("Value incorrect.")
+	}
+	pb := cs1.ToPbMessage()
+	if buf, e := json.MarshalIndent(pb, "", "\t");e == nil {
+		t.Log(string(buf))
+	}else{
+		t.Fatal(e)
+	}
+	cs2 := NewCollectionSettingsFromPbMessage(pb)
+	if !reflect.DeepEqual(cs1, cs2) {
+		t.Fatal("PbMessage convert incorrect.")
+	}
+}
diff --git a/go/storage/volume_super_block_test.go b/go/storage/volume_super_block_test.go
index 13db4b194..859f35110 100644
--- a/go/storage/volume_super_block_test.go
+++ b/go/storage/volume_super_block_test.go
@@ -5,12 +5,10 @@ import (
 )
 
 func TestSuperBlockReadWrite(t *testing.T) {
-	rp, _ := NewReplicaPlacementFromByte(byte(001))
 	ttl, _ := ReadTTL("15d")
 	s := &SuperBlock{
-		version:          CurrentVersion,
-		ReplicaPlacement: rp,
-		Ttl:              ttl,
+		version: CurrentVersion,
+		Ttl:     ttl,
 	}
 
 	bytes := s.Bytes()