[
https://issues.apache.org/jira/browse/HDFS-8298?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15087128#comment-15087128
]
Gokul commented on HDFS-8298:
-----------------------------
Hi [~qwertymaniac],
Do we know how to avoid Namenode shutdown due to long GC pauses? We are using
G1 Garbage collector and namenode shuts down due to the issue you've mentioned
when mixed GC takes place for more than 20 seconds
{quote}
It is important to understand why the writes timeout. Note that each write is
hardly more than a few thousand bytes, usually. Writing such a small amount, in
parallel and over the network, should not take > 2-3s. There's a LOT of factors
that can cause the timeouts besides the network: GC or other form of
process-level pauses (NN pauses mid-write over 20s, recovers, but write
finisher now thinks > 20s has passed to write to JNs, so it marks the write
failed)
{quote}
> HA: NameNode should not shut down completely without quorum, doesn't recover
> from temporary network outages
> -----------------------------------------------------------------------------------------------------------
>
> Key: HDFS-8298
> URL: https://issues.apache.org/jira/browse/HDFS-8298
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: ha, namenode, qjm
> Affects Versions: 2.6.0
> Reporter: Hari Sekhon
>
> In an HDFS HA setup if there is a temporary problem with contacting journal
> nodes (eg. network interruption), the NameNode shuts down entirely, when it
> should instead go in to a standby mode so that it can stay online and retry
> to achieve quorum later.
> If both NameNodes shut themselves off like this then even after the temporary
> network outage is resolved, the entire cluster remains offline indefinitely
> until operator intervention, whereas it could have self-repaired after
> re-contacting the journalnodes and re-achieving quorum.
> {code}2015-04-15 15:59:26,900 FATAL namenode.FSEditLog
> (JournalSet.java:mapJournalsAndReportErrors(398)) - Error: flush failed for
> required journal (JournalAndStre
> am(mgr=QJM to [<ip>:8485, <ip>:8485, <ip>:8485], stream=QuorumOutputStream
> starting at txid 54270281))
> java.io.IOException: Interrupted waiting 20000ms for a quorum of nodes to
> respond.
> at
> org.apache.hadoop.hdfs.qjournal.client.AsyncLoggerSet.waitForWriteQuorum(AsyncLoggerSet.java:134)
> at
> org.apache.hadoop.hdfs.qjournal.client.QuorumOutputStream.flushAndSync(QuorumOutputStream.java:107)
> at
> org.apache.hadoop.hdfs.server.namenode.EditLogOutputStream.flush(EditLogOutputStream.java:113)
> at
> org.apache.hadoop.hdfs.server.namenode.EditLogOutputStream.flush(EditLogOutputStream.java:107)
> at
> org.apache.hadoop.hdfs.server.namenode.JournalSet$JournalSetOutputStream$8.apply(JournalSet.java:533)
> at
> org.apache.hadoop.hdfs.server.namenode.JournalSet.mapJournalsAndReportErrors(JournalSet.java:393)
> at
> org.apache.hadoop.hdfs.server.namenode.JournalSet.access$100(JournalSet.java:57)
> at
> org.apache.hadoop.hdfs.server.namenode.JournalSet$JournalSetOutputStream.flush(JournalSet.java:529)
> at
> org.apache.hadoop.hdfs.server.namenode.FSEditLog.logSync(FSEditLog.java:639)
> at
> org.apache.hadoop.hdfs.server.namenode.LeaseManager$Monitor.run(LeaseManager.java:388)
> at java.lang.Thread.run(Thread.java:745)
> 2015-04-15 15:59:26,901 WARN client.QuorumJournalManager
> (QuorumOutputStream.java:abort(72)) - Aborting QuorumOutputStream starting at
> txid 54270281
> 2015-04-15 15:59:26,904 INFO util.ExitUtil (ExitUtil.java:terminate(124)) -
> Exiting with status 1
> 2015-04-15 15:59:27,001 INFO namenode.NameNode (StringUtils.java:run(659)) -
> SHUTDOWN_MSG:
> /************************************************************
> SHUTDOWN_MSG: Shutting down NameNode at <custom_scrubbed>/<ip>
> ************************************************************/{code}
> Hari Sekhon
> http://www.linkedin.com/in/harisekhon
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
