org.apache.hadoop.hdfs.server.datanode
Class RoundRobinVolumesPolicy

java.lang.Object
  org.apache.hadoop.hdfs.server.datanode.RoundRobinVolumesPolicy

All Implemented Interfaces:

BlockVolumeChoosingPolicy

public class RoundRobinVolumesPolicy
extends Object
implements BlockVolumeChoosingPolicy

Constructor Summary

RoundRobinVolumesPolicy()

Method Summary

org.apache.hadoop.hdfs.server.datanode.FSDataset.FSVolume

chooseVolume(List<org.apache.hadoop.hdfs.server.datanode.FSDataset.FSVolume> volumes, long blockSize) Returns a specific FSVolume after applying a suitable choice algorithm to place a given block, given a list of FSVolumes and the block size sought for storage.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RoundRobinVolumesPolicy

public RoundRobinVolumesPolicy()

Method Detail

chooseVolume

public org.apache.hadoop.hdfs.server.datanode.FSDataset.FSVolume chooseVolume(List<org.apache.hadoop.hdfs.server.datanode.FSDataset.FSVolume> volumes,
                                                                              long blockSize)
                                                                       throws IOException

Description copied from interface: BlockVolumeChoosingPolicy

Returns a specific FSVolume after applying a suitable choice algorithm to place a given block, given a list of FSVolumes and the block size sought for storage. (Policies that maintain state must be thread-safe.)

Specified by:

chooseVolume in interface BlockVolumeChoosingPolicy

Parameters:

volumes - - the array of FSVolumes that are available.

blockSize - - the size of the block for which a volume is sought.

Returns:

the chosen volume to store the block.

Throws:

IOException - when disks are unavailable or are full.