org.apache.hadoop.hdfs.server.datanode.fsdataset

Interface VolumeChoosingPolicy<V extends FsVolumeSpi>

All Known Implementing Classes:

AvailableSpaceVolumeChoosingPolicy, RoundRobinVolumeChoosingPolicy

@InterfaceAudience.Private
public interface VolumeChoosingPolicy<V extends FsVolumeSpi>

This interface specifies the policy for choosing volumes to store replicas.

Method Summary

Methods

Modifier and Type	Method and Description
V	chooseVolume(List<V> volumes, long replicaSize) Choose a volume to place a replica, given a list of volumes and the replica size sought for storage.

Method Detail

chooseVolume

V chooseVolume(List<V> volumes,
             long replicaSize)
                                   throws IOException

Choose a volume to place a replica, given a list of volumes and the replica size sought for storage. The implementations of this interface must be thread-safe.

Parameters:

volumes - - a list of available volumes.

replicaSize - - the size of the replica for which a volume is sought.

Returns:

the chosen volume.

Throws:

IOException - when disks are unavailable or are full.