[jira] [Updated] (ZOOKEEPER-1621) ZooKeeper does not recover from crash when disk was full

["Abhishek Rai (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ZOOKEEPER-1621?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Abhishek Rai updated ZOOKEEPER-1621:
------------------------------------
    Attachment: ZOOKEEPER-1621.2.patch

Based on the discussion with [~mkizner] above, skipping of the truncated txn log file is insufficient, and its deletion is necessary.  Otherwise we can run into problems in two places:

- FileTxnLog is required to include the latest txn log before the snapshot that it's loading.  If that latest txn log is truncated (and previously skipped), then it can incorrectly satisfy this requirement.  Instead, if we delete the truncated file, then we are forced to reach back into the older valid txn log.

- PurgeTxnLog has similar logic about retaining the latest txn log before the last retained snapshot.  Therefore, without the deletion, its requirements would similarly be met by a truncated and useless txn log.

I've now updated [~michim]'s patch with two changes and corresponding testing changes:
- Deletion as described here.
- Use a tighter exception (EOFException) instead of IOException.

> 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: 3.5.3, 3.6.0
>
>         Attachments: ZOOKEEPER-1621.2.patch, 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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