diff --git a/weed/cluster/lock_manager/distributed_lock_manager.go b/weed/cluster/lock_manager/distributed_lock_manager.go
index b78c62b00..7577fb830 100644
--- a/weed/cluster/lock_manager/distributed_lock_manager.go
+++ b/weed/cluster/lock_manager/distributed_lock_manager.go
@@ -6,6 +6,8 @@ import (
 	"time"
 )
 
+var NoLockServerError = fmt.Errorf("no lock server found")
+
 type DistributedLockManager struct {
 	lockManager *LockManager
 	LockRing    *LockRing
@@ -21,7 +23,7 @@ func NewDistributedLockManager() *DistributedLockManager {
 func (dlm *DistributedLockManager) Lock(host pb.ServerAddress, key string, expiredAtNs int64, token string) (renewToken string, movedTo pb.ServerAddress, err error) {
 	servers := dlm.LockRing.GetSnapshot()
 	if servers == nil {
-		err = fmt.Errorf("no lock server found")
+		err = NoLockServerError
 		return
 	}
 
@@ -37,7 +39,7 @@ func (dlm *DistributedLockManager) Lock(host pb.ServerAddress, key string, expir
 func (dlm *DistributedLockManager) Unlock(host pb.ServerAddress, key string, token string) (movedTo pb.ServerAddress, err error) {
 	servers := dlm.LockRing.GetSnapshot()
 	if servers == nil {
-		err = fmt.Errorf("no lock server found")
+		err = NoLockServerError
 		return
 	}
 
diff --git a/weed/cluster/lock_manager/lock_manager.go b/weed/cluster/lock_manager/lock_manager.go
index 57fb34819..2c2ebe387 100644
--- a/weed/cluster/lock_manager/lock_manager.go
+++ b/weed/cluster/lock_manager/lock_manager.go
@@ -7,6 +7,11 @@ import (
 	"time"
 )
 
+var LockErrorNonEmptyTokenOnNewLock = fmt.Errorf("lock: non-empty token on a new lock")
+var LockErrorNonEmptyTokenOnExpiredLock = fmt.Errorf("lock: non-empty token on an expired lock")
+var LockErrorTokenMismatch = fmt.Errorf("lock: token mismatch")
+var UnlockErrorTokenMismatch = fmt.Errorf("unlock: token mismatch")
+
 // LockManager lock manager
 type LockManager struct {
 	locks *xsync.MapOf[string, *Lock]
@@ -31,7 +36,7 @@ func (lm *LockManager) Lock(path string, expiredAtNs int64, token string) (renew
 			if oldValue.ExpiredAtNs > 0 && oldValue.ExpiredAtNs < time.Now().UnixNano() {
 				// lock is expired, set to a new lock
 				if token != "" {
-					err = fmt.Errorf("lock: non-empty token on an expired lock")
+					err = LockErrorNonEmptyTokenOnExpiredLock
 					return nil, false
 				} else {
 					// new lock
@@ -45,7 +50,7 @@ func (lm *LockManager) Lock(path string, expiredAtNs int64, token string) (renew
 				renewToken = uuid.New().String()
 				return &Lock{Token: renewToken, ExpiredAtNs: expiredAtNs}, false
 			} else {
-				err = fmt.Errorf("lock: token mismatch")
+				err = LockErrorTokenMismatch
 				return oldValue, false
 			}
 		} else {
@@ -54,7 +59,7 @@ func (lm *LockManager) Lock(path string, expiredAtNs int64, token string) (renew
 				renewToken = uuid.New().String()
 				return &Lock{Token: renewToken, ExpiredAtNs: expiredAtNs}, false
 			} else {
-				err = fmt.Errorf("lock: non-empty token on a new lock")
+				err = LockErrorNonEmptyTokenOnNewLock
 				return nil, false
 			}
 		}
@@ -79,7 +84,7 @@ func (lm *LockManager) Unlock(path string, token string) (isUnlocked bool, err e
 				return oldValue, false
 			} else {
 				isUnlocked = false
-				err = fmt.Errorf("unlock: token mismatch")
+				err = UnlockErrorTokenMismatch
 				return oldValue, false
 			}
 		} else {