[jira] [Assigned] (HDFS-12288) Fix DataNode's xceiver count calculation
[ https://issues.apache.org/jira/browse/HDFS-12288?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Lisheng Sun reassigned HDFS-12288: -- Assignee: Lisheng Sun (was: Chen Zhang) > Fix DataNode's xceiver count calculation > > > Key: HDFS-12288 > URL: https://issues.apache.org/jira/browse/HDFS-12288 > Project: Hadoop HDFS > Issue Type: Bug > Components: datanode, hdfs >Reporter: Lukas Majercak >Assignee: Lisheng Sun >Priority: Major > Attachments: HDFS-12288.001.patch, HDFS-12288.002.patch, > HDFS-12288.003.patch, HDFS-12288.004.patch, HDFS-12288.005.patch, > HDFS-12288.006.patch, HDFS-12288.007.patch, HDFS-12288.008.patch > > > The problem with the ThreadGroup.activeCount() method is that the method is > only a very rough estimate, and in reality returns the total number of > threads in the thread group as opposed to the threads actually running. > In some DNs, we saw this to return 50~ for a long time, even though the > actual number of DataXceiver threads was next to none. > This is a big issue as we use the xceiverCount to make decisions on the NN > for choosing replication source DN or returning DNs to clients for R/W. > The plan is to reuse the DataNodeMetrics.dataNodeActiveXceiversCount value > which only accounts for actual number of DataXcevier threads currently > running and thus represents the load on the DN much better. -- This message was sent by Atlassian Jira (v8.3.4#803005) - To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
[jira] [Assigned] (HDFS-12288) Fix DataNode's xceiver count calculation
[ https://issues.apache.org/jira/browse/HDFS-12288?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Chen Zhang reassigned HDFS-12288: - Assignee: Chen Zhang (was: Lukas Majercak) > Fix DataNode's xceiver count calculation > > > Key: HDFS-12288 > URL: https://issues.apache.org/jira/browse/HDFS-12288 > Project: Hadoop HDFS > Issue Type: Bug > Components: datanode, hdfs >Reporter: Lukas Majercak >Assignee: Chen Zhang >Priority: Major > Attachments: HDFS-12288.001.patch, HDFS-12288.002.patch, > HDFS-12288.003.patch > > > The problem with the ThreadGroup.activeCount() method is that the method is > only a very rough estimate, and in reality returns the total number of > threads in the thread group as opposed to the threads actually running. > In some DNs, we saw this to return 50~ for a long time, even though the > actual number of DataXceiver threads was next to none. > This is a big issue as we use the xceiverCount to make decisions on the NN > for choosing replication source DN or returning DNs to clients for R/W. > The plan is to reuse the DataNodeMetrics.dataNodeActiveXceiversCount value > which only accounts for actual number of DataXcevier threads currently > running and thus represents the load on the DN much better. -- This message was sent by Atlassian Jira (v8.3.2#803003) - To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
