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Posted to issues@hbase.apache.org by "Vladimir Rodionov (JIRA)" <ji...@apache.org> on 2015/10/01 02:31:04 UTC
[jira] [Commented] (HBASE-14522) Document and/or disable hsperfdata
GC pauses
[ https://issues.apache.org/jira/browse/HBASE-14522?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14939104#comment-14939104 ]
Vladimir Rodionov commented on HBASE-14522:
-------------------------------------------
Needs to be documented:
https://issues.apache.org/jira/browse/CASSANDRA-9483
> Document and/or disable hsperfdata GC pauses
> --------------------------------------------
>
> Key: HBASE-14522
> URL: https://issues.apache.org/jira/browse/HBASE-14522
> Project: HBase
> Issue Type: Task
> Components: documentation, Performance
> Reporter: Nick Dimiduk
> Assignee: Lars Francke
> Attachments: HBASE-14522.patch
>
>
> {quote}
> The JVM by default exports statistics by mmap-ing a file in /tmp (hsperfdata). On Linux, modifying a memory mapped file can block until disk I/O completes, which can be hundreds of milliseconds. Since the JVM modifies these statistics during garbage collection and safepoints, this causes pauses that are hundreds of milliseconds long.
> {quote}
> Via [JVM mmap pause|http://www.evanjones.ca/jvm-mmap-pause.html].
> We should add {{-XX:+PerfDisableSharedMem}} to our default options as was apparently done in CASSANDRA-9242 and/or document the presence of this bug so operators know to use tmpfs.
> Hat-tip [~vrodionov]
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