Add option in volume.fix.replication to only fix under-replication and not delete volumes (#3640)

weed/shell/command_volume_fix_replication.go

@@ -57,6 +57,7 @@ func (c *commandVolumeFixReplication) Do(args []string, commandEnv *CommandEnv,
 	volFixReplicationCommand := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
 	c.collectionPattern = volFixReplicationCommand.String("collectionPattern", "", "match with wildcard characters '*' and '?'")
 	skipChange := volFixReplicationCommand.Bool("n", false, "skip the changes")
+	noDelete := volFixReplicationCommand.Bool("noDelete", false, "Do not delete over-replicated volumes, only fix under-replication")
 	retryCount := volFixReplicationCommand.Int("retry", 0, "how many times to retry")
 	volumesPerStep := volFixReplicationCommand.Int("volumesPerStep", 0, "how many volumes to fix in one cycle")
 
@@ -69,6 +70,7 @@ func (c *commandVolumeFixReplication) Do(args []string, commandEnv *CommandEnv,
 	}
 
 	takeAction := !*skipChange
+	doDeletes := !*noDelete;
 
 	underReplicatedVolumeIdsCount := 1
 	for underReplicatedVolumeIdsCount > 0 {
@@ -108,13 +110,13 @@ func (c *commandVolumeFixReplication) Do(args []string, commandEnv *CommandEnv,
 			return fmt.Errorf("lock is lost")
 		}
 
-		if len(overReplicatedVolumeIds) > 0 {
+		if len(overReplicatedVolumeIds) > 0 && doDeletes {
 			if err := c.deleteOneVolume(commandEnv, writer, takeAction, overReplicatedVolumeIds, volumeReplicas, allLocations, pickOneReplicaToDelete); err != nil {
 				return err
 			}
 		}
 
-		if len(misplacedVolumeIds) > 0 {
+		if len(misplacedVolumeIds) > 0 && doDeletes {
 			if err := c.deleteOneVolume(commandEnv, writer, takeAction, misplacedVolumeIds, volumeReplicas, allLocations, pickOneMisplacedVolume); err != nil {
 				return err
 			}