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https://issues.apache.org/jira/browse/ZOOKEEPER-1621?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14004109#comment-14004109
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Alexander Shraer commented on ZOOKEEPER-1621:
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Here's a different option - intuitively once zookeeper fails to write to disk,
by continuing to operate normally it violates its promises to users (which is
that if a majority acked the data is always there even if reboots happen). Once
we realize the promise can't be kept it may be better to crash the server at
that point and violate liveness (no availability) rather than to continue and
risk coming up with a partial log at a later point violating safety
(inconsistent state, lost transactions, etc).
> ZooKeeper does not recover from crash when disk was full
> --------------------------------------------------------
>
> Key: ZOOKEEPER-1621
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1621
> Project: ZooKeeper
> Issue Type: Bug
> Components: server
> Affects Versions: 3.4.3
> Environment: Ubuntu 12.04, Amazon EC2 instance
> Reporter: David Arthur
> Assignee: Michi Mutsuzaki
> Fix For: 3.5.0
>
> Attachments: ZOOKEEPER-1621.patch, zookeeper.log.gz
>
>
> The disk that ZooKeeper was using filled up. During a snapshot write, I got
> the following exception
> 2013-01-16 03:11:14,098 - ERROR [SyncThread:0:SyncRequestProcessor@151] -
> Severe unrecoverable error, exiting
> java.io.IOException: No space left on device
> at java.io.FileOutputStream.writeBytes(Native Method)
> at java.io.FileOutputStream.write(FileOutputStream.java:282)
> at
> java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
> at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
> at
> org.apache.zookeeper.server.persistence.FileTxnLog.commit(FileTxnLog.java:309)
> at
> org.apache.zookeeper.server.persistence.FileTxnSnapLog.commit(FileTxnSnapLog.java:306)
> at org.apache.zookeeper.server.ZKDatabase.commit(ZKDatabase.java:484)
> at
> org.apache.zookeeper.server.SyncRequestProcessor.flush(SyncRequestProcessor.java:162)
> at
> org.apache.zookeeper.server.SyncRequestProcessor.run(SyncRequestProcessor.java:101)
> Then many subsequent exceptions like:
> 2013-01-16 15:02:23,984 - ERROR [main:Util@239] - Last transaction was
> partial.
> 2013-01-16 15:02:23,985 - ERROR [main:ZooKeeperServerMain@63] - Unexpected
> exception, exiting abnormally
> java.io.EOFException
> at java.io.DataInputStream.readInt(DataInputStream.java:375)
> at
> org.apache.jute.BinaryInputArchive.readInt(BinaryInputArchive.java:63)
> at
> org.apache.zookeeper.server.persistence.FileHeader.deserialize(FileHeader.java:64)
> at
> org.apache.zookeeper.server.persistence.FileTxnLog$FileTxnIterator.inStreamCreated(FileTxnLog.java:558)
> at
> org.apache.zookeeper.server.persistence.FileTxnLog$FileTxnIterator.createInputArchive(FileTxnLog.java:577)
> at
> org.apache.zookeeper.server.persistence.FileTxnLog$FileTxnIterator.goToNextLog(FileTxnLog.java:543)
> at
> org.apache.zookeeper.server.persistence.FileTxnLog$FileTxnIterator.next(FileTxnLog.java:625)
> at
> org.apache.zookeeper.server.persistence.FileTxnLog$FileTxnIterator.init(FileTxnLog.java:529)
> at
> org.apache.zookeeper.server.persistence.FileTxnLog$FileTxnIterator.<init>(FileTxnLog.java:504)
> at
> org.apache.zookeeper.server.persistence.FileTxnLog.read(FileTxnLog.java:341)
> at
> org.apache.zookeeper.server.persistence.FileTxnSnapLog.restore(FileTxnSnapLog.java:130)
> at
> org.apache.zookeeper.server.ZKDatabase.loadDataBase(ZKDatabase.java:223)
> at
> org.apache.zookeeper.server.ZooKeeperServer.loadData(ZooKeeperServer.java:259)
> at
> org.apache.zookeeper.server.ZooKeeperServer.startdata(ZooKeeperServer.java:386)
> at
> org.apache.zookeeper.server.NIOServerCnxnFactory.startup(NIOServerCnxnFactory.java:138)
> at
> org.apache.zookeeper.server.ZooKeeperServerMain.runFromConfig(ZooKeeperServerMain.java:112)
> 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)
> It seems to me that writing the transaction log should be fully atomic to
> avoid such situations. Is this not the case?
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