diff --git a/pkg/hostman/storageman/backup.go b/pkg/hostman/storageman/backup.go
index f54a8ecda6..1783c28d09 100644
--- a/pkg/hostman/storageman/backup.go
+++ b/pkg/hostman/storageman/backup.go
@@ -201,7 +201,7 @@ func DoInstancePackBackup(ctx context.Context, backupInfo SStoragePackInstanceBa
 		} else {
 			finalPackageFileName = fmt.Sprintf("%s-%d.tar", backupInfo.PackageName, tried)
 		}
-		exists, err := backupStorage.IsBackupInstanceExists(finalPackageFileName)
+		exists, _, err := backupStorage.IsBackupInstanceExists(finalPackageFileName)
 		if err != nil {
 			return "", errors.Wrap(err, "IsBackupInstanceExists")
 		}
diff --git a/pkg/hostman/storageman/backupstorage/backup_storage.go b/pkg/hostman/storageman/backupstorage/backup_storage.go
index cc6472a227..5f6ebdfa72 100644
--- a/pkg/hostman/storageman/backupstorage/backup_storage.go
+++ b/pkg/hostman/storageman/backupstorage/backup_storage.go
@@ -34,7 +34,7 @@ type IBackupStorage interface {
 	// 删除备份
 	RemoveBackup(ctx context.Context, backupId string) error
 	// 备份是否存在
-	IsBackupExists(backupId string) (bool, error)
+	IsBackupExists(backupId string) (bool, string, error)
 
 	// 从指定路径拷贝主机备份文件到备份存储
 	SaveBackupInstanceFrom(ctx context.Context, srcFilename string, bakcupInstanceId string) error
@@ -43,7 +43,7 @@ type IBackupStorage interface {
 	// 删除备份
 	RemoveBackupInstance(ctx context.Context, backupInstanceId string) error
 	// 备份是否存在
-	IsBackupInstanceExists(backupInstanceId string) (bool, error)
+	IsBackupInstanceExists(backupInstanceId string) (bool, string, error)
 
 	// ConvertTo(destPath string, format qemuimgfmt.TImageFormat, backupId string) error
 	// ConvertFrom(srcPath string, format qemuimgfmt.TImageFormat, backupId string) (int, error)
diff --git a/pkg/hostman/storageman/backupstorage/nfs/nfs.go b/pkg/hostman/storageman/backupstorage/nfs/nfs.go
index 69a5b35065..4ffe6fd47a 100644
--- a/pkg/hostman/storageman/backupstorage/nfs/nfs.go
+++ b/pkg/hostman/storageman/backupstorage/nfs/nfs.go
@@ -194,31 +194,34 @@ func (s *SNFSBackupStorage) removeFile(ctx context.Context, id string, getPathFu
 	return nil
 }
 
-func (s *SNFSBackupStorage) IsBackupExists(backupId string) (bool, error) {
+func (s *SNFSBackupStorage) IsBackupExists(backupId string) (bool, string, error) {
 	return s.isFileExists(backupId, s.getBackupDiskPath)
 }
 
-func (s *SNFSBackupStorage) IsBackupInstanceExists(backupId string) (bool, error) {
+func (s *SNFSBackupStorage) IsBackupInstanceExists(backupId string) (bool, string, error) {
 	return s.isFileExists(backupId, s.getBackupInstancePath)
 }
 
-func (s *SNFSBackupStorage) isFileExists(id string, getPathFunc func(id string) string) (bool, error) {
+func (s *SNFSBackupStorage) isFileExists(id string, getPathFunc func(id string) string) (bool, string, error) {
 	err := s.checkAndMount()
 	if err != nil {
-		return false, errors.Wrap(err, "unable to checkAndMount")
+		if errors.Cause(err) == ErrorBackupStorageOffline {
+			return false, err.Error(), nil
+		}
+		return false, "", errors.Wrap(err, "unable to checkAndMount")
 	}
 	defer s.unMount()
 
 	filename := getPathFunc(id)
-	return fileutils2.Exists(filename), nil
+	return fileutils2.Exists(filename), "", nil
 }
 
 func (s *SNFSBackupStorage) IsOnline() (bool, string, error) {
 	err := s.checkAndMount()
-	if errors.Cause(err) == ErrorBackupStorageOffline {
-		return false, err.Error(), nil
-	}
 	if err != nil {
+		if errors.Cause(err) == ErrorBackupStorageOffline {
+			return false, err.Error(), nil
+		}
 		return false, "", err
 	}
 	s.unMount()
diff --git a/pkg/hostman/storageman/backupstorage/object/object.go b/pkg/hostman/storageman/backupstorage/object/object.go
index 2fc9413e29..c4ca38ea79 100644
--- a/pkg/hostman/storageman/backupstorage/object/object.go
+++ b/pkg/hostman/storageman/backupstorage/object/object.go
@@ -178,27 +178,27 @@ func (s *SObjectBackupStorage) removeObject(ctx context.Context, id string, getK
 	return nil
 }
 
-func (s *SObjectBackupStorage) IsBackupExists(backupId string) (bool, error) {
+func (s *SObjectBackupStorage) IsBackupExists(backupId string) (bool, string, error) {
 	return s.isObjectExists(backupId, s.getBackupKey)
 }
 
-func (s *SObjectBackupStorage) IsBackupInstanceExists(backupId string) (bool, error) {
+func (s *SObjectBackupStorage) IsBackupInstanceExists(backupId string) (bool, string, error) {
 	return s.isObjectExists(backupId, s.getBackupInstanceKey)
 }
 
-func (s *SObjectBackupStorage) isObjectExists(id string, getKeyFunc func(string) string) (bool, error) {
+func (s *SObjectBackupStorage) isObjectExists(id string, getKeyFunc func(string) string) (bool, string, error) {
 	bucket, err := s.getBucket()
 	if err != nil {
-		return false, errors.Wrap(err, "getBucket")
+		return false, "", errors.Wrap(err, "getBucket")
 	}
 	_, err = cloudprovider.GetIObject(bucket, getKeyFunc(id))
 	if err != nil {
 		if errors.Cause(err) == errors.ErrNotFound {
-			return false, nil
+			return false, "", nil
 		}
-		return false, errors.Wrap(err, "GetIObject")
+		return false, "", errors.Wrap(err, "GetIObject")
 	}
-	return true, nil
+	return true, "", nil
 }
 
 func (s *SObjectBackupStorage) IsOnline() (bool, string, error) {
diff --git a/pkg/hostman/storageman/storagehandler/storagehandler.go b/pkg/hostman/storageman/storagehandler/storagehandler.go
index 7c7444566a..71eef99bf9 100644
--- a/pkg/hostman/storageman/storagehandler/storagehandler.go
+++ b/pkg/hostman/storageman/storagehandler/storagehandler.go
@@ -276,7 +276,7 @@ func storageSyncBackup(ctx context.Context, w http.ResponseWriter, r *http.Reque
 		hostutils.Response(ctx, w, err)
 		return
 	}
-	exist, err := backupStorage.IsBackupExists(backupId)
+	exist, reason, err := backupStorage.IsBackupExists(backupId)
 	if err != nil {
 		hostutils.Response(ctx, w, err)
 		return
@@ -287,11 +287,13 @@ func storageSyncBackup(ctx context.Context, w http.ResponseWriter, r *http.Reque
 	)
 	if exist {
 		status = compute.BACKUP_EXIST
-	} else if !exist && err == nil {
-		status = compute.BACKUP_NOT_EXIST
 	} else {
-		log.Errorf("fetch snapshot exist failed %s", err)
-		status = compute.BACKUP_STATUS_UNKNOWN
+		if len(reason) == 0 {
+			status = compute.BACKUP_NOT_EXIST
+		} else {
+			log.Errorf("fetch snapshot exist failed reason:%s", reason)
+			status = compute.BACKUP_STATUS_UNKNOWN
+		}
 	}
 	ret.Set("status", jsonutils.NewString(status))
 	hostutils.Response(ctx, w, ret)