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https://issues.apache.org/jira/browse/ZOOKEEPER-1936?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15397513#comment-15397513
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David Arthur commented on ZOOKEEPER-1936:
-----------------------------------------
Are there any known scenarios that will trigger this race? We've seen it
intermittently in an EC2 environment, but have yet to figure out why it happens
there and not other environments.
Also, any updates on the status of this issue?
> Server exits when unable to create data directory due to race
> --------------------------------------------------------------
>
> Key: ZOOKEEPER-1936
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1936
> Project: ZooKeeper
> Issue Type: Bug
> Components: server
> Affects Versions: 3.4.6, 3.5.0
> Reporter: Harald Musum
> Assignee: Andrew Purtell
> Priority: Minor
> Attachments: ZOOKEEPER-1936.patch, ZOOKEEPER-1936.v2.patch,
> ZOOKEEPER-1936.v3.patch, ZOOKEEPER-1936.v3.patch, ZOOKEEPER-1936.v4.patch
>
>
> We sometime see issues with ZooKeeper server not starting and seeing this
> error in the log:
> [2014-05-27 09:29:48.248] ERROR : -
> .org.apache.zookeeper.server.ZooKeeperServerMain Unexpected exception,
> exiting abnormally\nexception=\njava.io.IOException: Unable to create data
> directory /home/y/var/zookeeper/version-2\n\tat
> org.apache.zookeeper.server.persistence.FileTxnSnapLog.<init>(FileTxnSnapLog.java:85)\n\tat
> org.apache.zookeeper.server.ZooKeeperServerMain.runFromConfig(ZooKeeperServerMain.java:103)\n\tat
> org.apache.zookeeper.server.ZooKeeperServerMain.initializeAndRun(ZooKeeperServerMain.java:86)\n\tat
> org.apache.zookeeper.server.ZooKeeperServerMain.main(ZooKeeperServerMain.java:52)\n\tat
> org.apache.zookeeper.server.quorum.QuorumPeerMain.initializeAndRun(QuorumPeerMain.java:116)\n\tat
> org.apache.zookeeper.server.quorum.QuorumPeerMain.main(QuorumPeerMain.java:78)\n\t
> [...]
> Stack trace from JVM gives this:
> "PurgeTask" daemon prio=10 tid=0x000000000201d000 nid=0x1727 runnable
> [0x00007f55d7dc7000]
> java.lang.Thread.State: RUNNABLE
> at java.io.UnixFileSystem.createDirectory(Native Method)
> at java.io.File.mkdir(File.java:1310)
> at java.io.File.mkdirs(File.java:1337)
> at
> org.apache.zookeeper.server.persistence.FileTxnSnapLog.<init>(FileTxnSnapLog.java:84)
> at org.apache.zookeeper.server.PurgeTxnLog.purge(PurgeTxnLog.java:68)
> at
> org.apache.zookeeper.server.DatadirCleanupManager$PurgeTask.run(DatadirCleanupManager.java:140)
> at java.util.TimerThread.mainLoop(Timer.java:555)
> at java.util.TimerThread.run(Timer.java:505)
> "zookeeper server" prio=10 tid=0x00000000027df800 nid=0x1715 runnable
> [0x00007f55d7ed8000]
> java.lang.Thread.State: RUNNABLE
> at java.io.UnixFileSystem.createDirectory(Native Method)
> at java.io.File.mkdir(File.java:1310)
> at java.io.File.mkdirs(File.java:1337)
> at
> org.apache.zookeeper.server.persistence.FileTxnSnapLog.<init>(FileTxnSnapLog.java:84)
> at
> org.apache.zookeeper.server.ZooKeeperServerMain.runFromConfig(ZooKeeperServerMain.java:103)
> at
> org.apache.zookeeper.server.ZooKeeperServerMain.initializeAndRun(ZooKeeperServerMain.java:86)
> at
> org.apache.zookeeper.server.ZooKeeperServerMain.main(ZooKeeperServerMain.java:52)
> at
> org.apache.zookeeper.server.quorum.QuorumPeerMain.initializeAndRun(QuorumPeerMain.java:116)
> at
> org.apache.zookeeper.server.quorum.QuorumPeerMain.main(QuorumPeerMain.java:78)
> [...]
> So it seems that when autopurge is used (as it is in our case), it might
> happen at the same time as starting the server itself. In FileTxnSnapLog() it
> will check if the directory exists and create it if not. These two tasks do
> this at the same time, and mkdir fails and server exits the JVM.
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