volume.balance: balance read only volumes first

weed/shell/command_volume_balance.go

@@ -120,7 +120,7 @@ func balanceVolumeServers(commandEnv *CommandEnv, diskTypes []types.DiskType, vo
 
 func balanceVolumeServersByDiskType(commandEnv *CommandEnv, diskType types.DiskType, volumeReplicas map[uint32][]*VolumeReplica, nodes []*Node, volumeSizeLimit uint64, collection string, applyBalancing bool) error {
 
-	// balance writable volumes
+	// balance readable volumes
 	for _, n := range nodes {
 		n.selectVolumes(func(v *master_pb.VolumeInformationMessage) bool {
 			if collection != "ALL_COLLECTIONS" {
@@ -128,14 +128,14 @@ func balanceVolumeServersByDiskType(commandEnv *CommandEnv, diskType types.DiskT
 					return false
 				}
 			}
-			return v.DiskType == string(diskType) && (!v.ReadOnly && v.Size < volumeSizeLimit)
+			return v.DiskType == string(diskType) && (v.ReadOnly || v.Size >= volumeSizeLimit)
 		})
 	}
-	if err := balanceSelectedVolume(commandEnv, volumeReplicas, nodes, capacityByMaxVolumeCount(diskType), sortWritableVolumes, applyBalancing); err != nil {
+	if err := balanceSelectedVolume(commandEnv, volumeReplicas, nodes, capacityByMaxVolumeCount(diskType), sortReadOnlyVolumes, applyBalancing); err != nil {
 		return err
 	}
 
-	// balance readable volumes
+	// balance writable volumes
 	for _, n := range nodes {
 		n.selectVolumes(func(v *master_pb.VolumeInformationMessage) bool {
 			if collection != "ALL_COLLECTIONS" {
@@ -143,10 +143,10 @@ func balanceVolumeServersByDiskType(commandEnv *CommandEnv, diskType types.DiskT
 					return false
 				}
 			}
-			return v.DiskType == string(diskType) && (v.ReadOnly || v.Size >= volumeSizeLimit)
+			return v.DiskType == string(diskType) && (!v.ReadOnly && v.Size < volumeSizeLimit)
 		})
 	}
-	if err := balanceSelectedVolume(commandEnv, volumeReplicas, nodes, capacityByMaxVolumeCount(diskType), sortReadOnlyVolumes, applyBalancing); err != nil {
+	if err := balanceSelectedVolume(commandEnv, volumeReplicas, nodes, capacityByMaxVolumeCount(diskType), sortWritableVolumes, applyBalancing); err != nil {
 		return err
 	}