[jira] [Commented] (AMBARI-18936) DataNode JVM heap settings should include CMSInitiatingOccupancy

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/AMBARI-18936?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15682063#comment-15682063 ] 

Hadoop QA commented on AMBARI-18936:
------------------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12839703/AMBARI-18936.02.patch
  against trunk revision .

    {color:green}+1 @author{color}.  The patch does not contain any @author tags.

    {color:red}-1 tests included{color}.  The patch doesn't appear to include any new or modified tests.
                        Please justify why no new tests are needed for this patch.
                        Also please list what manual steps were performed to verify this patch.

    {color:green}+1 javac{color}.  The applied patch does not increase the total number of javac compiler warnings.

    {color:green}+1 release audit{color}.  The applied patch does not increase the total number of release audit warnings.

    {color:green}+1 core tests{color}.  The patch passed unit tests in ambari-server.

Test results: https://builds.apache.org/job/Ambari-trunk-test-patch/9332//testReport/
Console output: https://builds.apache.org/job/Ambari-trunk-test-patch/9332//console

This message is automatically generated.

> DataNode JVM heap settings should include CMSInitiatingOccupancy
> ----------------------------------------------------------------
>
>                 Key: AMBARI-18936
>                 URL: https://issues.apache.org/jira/browse/AMBARI-18936
>             Project: Ambari
>          Issue Type: Improvement
>    Affects Versions: 2.2.2
>            Reporter: Arpit Agarwal
>            Assignee: Arpit Agarwal
>             Fix For: 2.5.0
>
>         Attachments: AMBARI-18936.02.patch
>
>
> This is a followup to AMBARI-18694 to fix remaining stack versions:
> ___________________________
> As HDFS-11047 reported, DirectoryScanner does scan by deep copying FinalizedReplica. In a deployment with 500,000+ blocks, we've seen the DN heap usage being accumulated to high peaks very quickly. Deep copies of FinalizedReplica will make DN heap usage even worse if directory scans are scheduled more frequently. 
> Another factor is that huge number of ScanInfo instances corresponding to HDFS blocks are lingering in garbage to eat many heap memories until a full GC takes place.
> This proposes adding JVM settings to force GC more frequently to release DataNode heap consumed as a result of two aforementioned reasons, i.e. add the options to HADOOP_DATANODE_OPTS
> {noformat}
> -XX:CMSInitiatingOccupancyFraction=70 -XX:+UseCMSInitiatingOccupancyOnly -XX:ConcGCThreads=8 -XX:+UseConcMarkSweepGC
> {noformat}



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)