org.apache.hadoop.hdfs.server.datanode

Class RoundRobinVolumesPolicy

java.lang.Object

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

All Implemented Interfaces:

org.apache.hadoop.hdfs.server.datanode.BlockVolumeChoosingPolicy

public class RoundRobinVolumesPolicy
extends Object
implements org.apache.hadoop.hdfs.server.datanode.BlockVolumeChoosingPolicy

Constructor Summary

Constructors

Constructor and Description
RoundRobinVolumesPolicy()

Method Summary

Methods

Modifier and Type	Method and Description
FSDatasetInterface.FSVolumeInterface	chooseVolume(List<FSDatasetInterface.FSVolumeInterface> 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 FSDatasetInterface.FSVolumeInterface chooseVolume(List<FSDatasetInterface.FSVolumeInterface> volumes,
                                                long blockSize)
                                                  throws IOException

Description copied from interface: org.apache.hadoop.hdfs.server.datanode.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 org.apache.hadoop.hdfs.server.datanode.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.