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https://issues.apache.org/jira/browse/HDFS-5889?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13897697#comment-13897697
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Vinayakumar B commented on HDFS-5889:
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Hi Nicholas,
Good work.
I have one doubt.
Current patch handles only saving fsimage in NameNodeFile.IMAGE_UPGRADE only by
StandbyCheckpointer in Standby Namenode. But when this is sent to Active
NameNode its being stored in NameNodeFile.IMAGE itself and purging also happens
on NameNodeFile.IMAGE.
Do you think in Active NameNode also ( even though its software not upgraded
yet ) checkpoint should be stored in NameNodeFile.IMAGE_UPGRADE when rolling
upgrade in progress?
> When rolling upgrade is in progress, standby NN should create checkpoint for
> downgrade.
> ---------------------------------------------------------------------------------------
>
> Key: HDFS-5889
> URL: https://issues.apache.org/jira/browse/HDFS-5889
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Reporter: Tsz Wo (Nicholas), SZE
> Assignee: Tsz Wo (Nicholas), SZE
> Attachments: h5889_20140211.patch
>
>
> After rolling upgrade is started and checkpoint is disabled, the edit log may
> grow to a huge size. It is not a problem if rolling upgrade is finalized
> normally since NN keeps the current state in memory and it writes a new
> checkpoint during finalize. However, it is a problem if admin decides to
> downgrade. It could take a long time to apply edit log. Rollback does not
> have such problem.
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