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https://issues.apache.org/jira/browse/HDFS-7587?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14284594#comment-14284594
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Tsz Wo Nicholas Sze commented on HDFS-7587:
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> ... The quotas aren't going to change so it seems calling verifyQuota
> explicitly is wasted processing time.
We may call verifyQuota in the beginning and update quota without checking at
the end.
> Do you have a scenario in mind? Ie. what is "later on"? Moving the file to UC
> and associating the lease aren't going to throw checked exceptions. ...
convertLastBlockToUnderConstruction does throw IOException.
> ... Even if that were to happen, an out of sync quota is better than a
> corrupted in-memory state and edit logs caused by the NN throwing runtime
> exceptions that don't cause an abort.
Agree. Out of sync quota is better than a corrupted in-memory state. Also,
in-sync quota is better than out of sync quota. We could have both in-sync
quota and uncorrupted in-memory state. I think no one is saying that we prefer
in-sync quota than uncorrupted in-memory state.
> Edit log corruption can happen if append fails with a quota violation
> ---------------------------------------------------------------------
>
> Key: HDFS-7587
> URL: https://issues.apache.org/jira/browse/HDFS-7587
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Reporter: Kihwal Lee
> Assignee: Daryn Sharp
> Priority: Blocker
> Attachments: HDFS-7587.patch
>
>
> We have seen a standby namenode crashing due to edit log corruption. It was
> complaining that {{OP_CLOSE}} cannot be applied because the file is not
> under-construction.
> When a client was trying to append to the file, the remaining space quota was
> very small. This caused a failure in {{prepareFileForWrite()}}, but after the
> inode was already converted for writing and a lease added. Since these were
> not undone when the quota violation was detected, the file was left in
> under-construction with an active lease without edit logging {{OP_ADD}}.
> A subsequent {{append()}} eventually caused a lease recovery after the soft
> limit period. This resulted in {{commitBlockSynchronization()}}, which closed
> the file with {{OP_CLOSE}} being logged. Since there was no corresponding
> {{OP_ADD}}, edit replaying could not apply this.
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