org.apache.hadoop.dfs
Class FSNamesystemMetrics

java.lang.Object
  org.apache.hadoop.dfs.FSNamesystemMetrics

All Implemented Interfaces:

Updater

public class FSNamesystemMetrics
extends Object
implements Updater

This class is for maintaining the various FSNamesystem status metrics and publishing them through the metrics interfaces. This also registers the JMX MBean for RPC.

This class has a number of metrics variables that are publicly accessible; these variables (objects) have methods to update their values; for example:

filesTotal.set()

Field Summary

MetricsIntValue	blocksTotal
MetricsIntValue	capacityRemainingGB
MetricsIntValue	capacityTotalGB
MetricsIntValue	capacityUsedGB
MetricsIntValue	filesTotal
MetricsIntValue	pendingReplicationBlocks
MetricsIntValue	scheduledReplicationBlocks
MetricsIntValue	totalLoad
MetricsIntValue	underReplicatedBlocks

Method Summary

void	doUpdates(MetricsContext unused) Since this object is a registered updater, this method will be called periodically, e.g.

Methods inherited from class java.lang.Object

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

Field Detail

filesTotal

public MetricsIntValue filesTotal

blocksTotal

public MetricsIntValue blocksTotal

capacityTotalGB

public MetricsIntValue capacityTotalGB

capacityUsedGB

public MetricsIntValue capacityUsedGB

capacityRemainingGB

public MetricsIntValue capacityRemainingGB

totalLoad

public MetricsIntValue totalLoad

pendingReplicationBlocks

public MetricsIntValue pendingReplicationBlocks

underReplicatedBlocks

public MetricsIntValue underReplicatedBlocks

scheduledReplicationBlocks

public MetricsIntValue scheduledReplicationBlocks

Method Detail

doUpdates

public void doUpdates(MetricsContext unused)

Since this object is a registered updater, this method will be called periodically, e.g. every 5 seconds. We set the metrics value within this function before pushing it out. FSNamesystem updates its own local variables which are light weight compared to Metrics counters. Some of the metrics are explicity casted to int. Few metrics collectors do not handle long values. It is safe to cast to int for now as all these values fit in int value. Metrics related to DFS capacity are stored in bytes which do not fit in int, so they are rounded to GB

Specified by:

doUpdates in interface Updater