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https://issues.apache.org/jira/browse/HDFS-7661?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15229367#comment-15229367
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Zhe Zhang commented on HDFS-7661:
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Addressing Mingliang's analysis first:
bq. what if the writer fails when the full stripe has not been sent to all
parity DNs? In this case, some of the parity DN has deleted the cellBuffers so
the last flushed data is not available any more, while the other parity DNs
have not received the parity cell for the full stripe.
In that case, any parity DN which "have not received the parity cell for the
full stripe" will have the cellBuffers. Note that we don't need all parity DNs
to have the full set of cellBuffers. As long as 1 parity DN has the full set of
cellBuffers we can recover to the state of the last successful flush.
> [umbrella] support hflush and hsync for erasure coded files
> -----------------------------------------------------------
>
> Key: HDFS-7661
> URL: https://issues.apache.org/jira/browse/HDFS-7661
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: erasure-coding
> Reporter: Tsz Wo Nicholas Sze
> Assignee: GAO Rui
> Attachments: EC-file-flush-and-sync-steps-plan-2015-12-01.png,
> HDFS-7661-unitTest-wip-trunk.patch, HDFS-7661-wip.01.patch,
> HDFS-EC-file-flush-sync-design-v20160323.pdf,
> HDFS-EC-file-flush-sync-design-version1.1.pdf, Undo-Log-Design-20160406.jpg
>
>
> We also need to support hflush/hsync and visible length.
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