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From "sam rash (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HDFS-1142) Lease recovery doesn't reassign lease when triggered by append()
Date Wed, 26 May 2010 02:04:33 GMT

    [ https://issues.apache.org/jira/browse/HDFS-1142?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12871475#action_12871475
] 

sam rash commented on HDFS-1142:
--------------------------------

hmm, the client never reacquires the lease in my example--it loses it, still is able to acquire
blocks and write to the DNs, but those blocks do not complete (client dies) and report to
the NN.  They are "lost" in that the lease recovery that completes by the NN will only know
the block was allocated, but not any locations.  The lease will be removed and the blocks
won't be recovered ever.

during this time, the client may have called sync/hflush and hence received acks for that
data. This is the violation I think that might occur. I've looked at trunk and I'm not seeing
how this is avoided there even...?

Thanks for your patience in discussing this--maybe there isn't a problem and I don't yet see
how even trunk handles this?

> Lease recovery doesn't reassign lease when triggered by append()
> ----------------------------------------------------------------
>
>                 Key: HDFS-1142
>                 URL: https://issues.apache.org/jira/browse/HDFS-1142
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: name-node
>    Affects Versions: 0.21.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>         Attachments: hdfs-1142.txt, hdfs-1142.txt
>
>
> If a soft lease has expired and another writer calls append(), it triggers lease recovery
but doesn't reassign the lease to a new owner. Therefore, the old writer can continue to allocate
new blocks, try to steal back the lease, etc. This is for the testRecoveryOnBlockBoundary
case of HDFS-1139

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