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https://issues.apache.org/jira/browse/HBASE-14522?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14947206#comment-14947206
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Yu Li commented on HBASE-14522:
-------------------------------
Above comment is a little bit ambiguous, so allow me to quote from the
cassandra JIRA:
{quote}
The default JVM flag -XX:+PerfDisableSharedMem will cause the following tools
JVM
to stop working. jps, jstack, jinfo, jmc, jcmd as well as 3rd party tools like
Jolokia.
{quote}
Since tools like jps, jstack, jinfo, etc. are necessary for maintenance and
problem debugging, maybe adding the option into hbase-env.sh but not as default
a better idea?
> 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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