handle volume not found when backing up

weed/command/backup.go

@@ -88,13 +88,24 @@ func runBackup(cmd *Command, args []string) bool {
 		fmt.Printf("Error looking up volume %d: %v\n", vid, err)
 		return true
 	}
-	volumeServer := lookup.Locations[0].ServerAddress()
+	if len(lookup.Locations) == 0 {
+		fmt.Printf("Error: volume %d has no locations available\n", vid)
+		return true
+	}
+
+	// Try each available location until one succeeds
+	var lastErr error
+	for i, location := range lookup.Locations {
+		volumeServer := location.ServerAddress()
+		fmt.Printf("Attempting to backup volume %d from location %d/%d: %s\n", vid, i+1, len(lookup.Locations), volumeServer)
 
 		stats, err := operation.GetVolumeSyncStatus(volumeServer, grpcDialOption, uint32(vid))
 		if err != nil {
-		fmt.Printf("Error get volume %d status: %v\n", vid, err)
-		return true
+			fmt.Printf("Error getting volume %d status from %s: %v\n", vid, volumeServer, err)
+			lastErr = err
+			continue
 		}
+
 		var ttl *needle.TTL
 		if *s.ttl != "" {
 			ttl, err = needle.ReadTTL(*s.ttl)
@@ -135,10 +146,12 @@ func runBackup(cmd *Command, args []string) bool {
 		if v.SuperBlock.CompactionRevision < uint16(stats.CompactRevision) {
 			if err = v.Compact2(0, 0, nil); err != nil {
 				fmt.Printf("Compact Volume before synchronizing %v\n", err)
+				v.Close()
 				return true
 			}
 			if err = v.CommitCompact(); err != nil {
 				fmt.Printf("Commit Compact before synchronizing %v\n", err)
+				v.Close()
 				return true
 			}
 			v.SuperBlock.CompactionRevision = uint16(stats.CompactRevision)
@@ -159,12 +172,23 @@ func runBackup(cmd *Command, args []string) bool {
 				return true
 			}
 		}
-	defer v.Close()
 
+		// Try the incremental backup
 		if err := v.IncrementalBackup(volumeServer, grpcDialOption); err != nil {
-		fmt.Printf("Error synchronizing volume %d: %v\n", vid, err)
+			fmt.Printf("Error synchronizing volume %d from %s: %v\n", vid, volumeServer, err)
+			v.Close()
+			lastErr = err
+			continue
+		}
+
+		// Success!
+		v.Close()
+		fmt.Printf("Successfully backed up volume %d from %s\n", vid, volumeServer)
 		return true
 	}
 
+	// All locations failed
+	fmt.Printf("Failed to backup volume %d after trying all %d locations. Last error: %v\n", vid, len(lookup.Locations), lastErr)
+
 	return true
 }