[jira] [Created] (HDFS-4128) 2NN gets stuck in inconsistent state if edit log replay fails in the middle

["Todd Lipcon (JIRA)" <ji...@apache.org>]

Todd Lipcon created HDFS-4128:
---------------------------------

             Summary: 2NN gets stuck in inconsistent state if edit log replay fails in the middle
                 Key: HDFS-4128
                 URL: https://issues.apache.org/jira/browse/HDFS-4128
             Project: Hadoop HDFS
          Issue Type: Bug
          Components: name-node
    Affects Versions: 2.0.2-alpha
            Reporter: Todd Lipcon


We saw the following issue in a cluster:
- The 2NN downloads an edit log segment:
{code}
2012-10-29 12:30:57,433 INFO org.apache.hadoop.hdfs.server.namenode.FSImage: Reading /xxxxxxx/current/edits_0000000000049136809-0000000000049176162 expecting start txid #49136809
{code}
- It fails in the middle of replay due to an OOME:
{code}
2012-10-29 12:31:21,021 ERROR org.apache.hadoop.hdfs.server.namenode.FSEditLogLoader: Encountered exception on operation AddOp [length=0, path=/xxxxxxxx
java.lang.OutOfMemoryError: Java heap space
{code}
- Future checkpoints then fail because the prior edit log replay only got halfway through the stream:
{code}
2012-10-29 12:32:21,214 INFO org.apache.hadoop.hdfs.server.namenode.FSImage: Reading /xxxxx/current/edits_0000000000049176163-0000000000049177224 expecting start txid #49144432
2012-10-29 12:32:21,216 ERROR org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: Exception in doCheckpoint
java.io.IOException: There appears to be a gap in the edit log.  We expected txid 49144432, but got txid 49176163.
{code}

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