Package org.apache.hadoop.hdfs.server.namenode.sps

Class DatanodeCacheManager

java.lang.Object

org.apache.hadoop.hdfs.server.namenode.sps.DatanodeCacheManager

@Private
public class DatanodeCacheManager
extends java.lang.Object

The Datanode cache Manager handles caching of DatanodeStorageReport. This class is instantiated by StoragePolicySatisifer. It maintains the array of datanode storage reports. It has a configurable refresh interval and periodically refresh the datanode cache by fetching latest Context.getLiveDatanodeStorageReport() once it reaches refresh interval.

Constructor Summary

Constructors

Constructor	Description
DatanodeCacheManager(org.apache.hadoop.conf.Configuration conf)

Method Summary

Modifier and Type	Method	Description
StoragePolicySatisfier.DatanodeMap	getLiveDatanodeStorageReport(Context spsContext)	Returns the live datanodes and its storage details, which has available space (> 0) to schedule block moves.

Methods inherited from class java.lang.Object

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

Constructor Detail

DatanodeCacheManager

public DatanodeCacheManager(org.apache.hadoop.conf.Configuration conf)

Method Detail

getLiveDatanodeStorageReport

public StoragePolicySatisfier.DatanodeMap getLiveDatanodeStorageReport(Context spsContext)
                                                                throws java.io.IOException

Returns the live datanodes and its storage details, which has available space (> 0) to schedule block moves. This will return array of datanodes from its local cache. It has a configurable refresh interval in millis and periodically refresh the datanode cache by fetching latest Context.getLiveDatanodeStorageReport() once it elapsed refresh interval.

Throws:

java.io.IOException