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https://issues.apache.org/jira/browse/HDFS-2017?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tsz Wo Nicholas Sze resolved HDFS-2017.
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Resolution: Not a Problem
I guess this old issue probably is not-a-problem anymore. Resolving ...
Please feel free to reopen this if you disagree.
> A partial rollback cause the new changes done after upgrade to be visible
> after rollback
> ----------------------------------------------------------------------------------------
>
> Key: HDFS-2017
> URL: https://issues.apache.org/jira/browse/HDFS-2017
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 0.20.1
> Reporter: SreeHari
> Priority: Minor
> Labels: rollback, upgrade
>
> This is the scenario :
> Namenode has 3 name dirs configured ..
> 1) Namenode upgrade starts - Upgrade fails after 1st directory is upgraded
> (2nd and 3rd dir is left unchanged ..) { like , Namenode process down }
> 2) Namenode starts and new files written ..
> 3) Namenode shutdown and rollbacked
> Since Namenode is saving the latest image dir(the upgraded 1st dir since
> checkpointtime is incremented during upgrade for this dir) will be loaded and
> saved to all dirs during loadfsimage ..
> But if a ROLLBACK is done , the 1st dir will be rolled back (the older copy
> becomes current and its checkpointtime is now LESS than other dirs ..) and
> others left behind since they dont contain previous .. Now during loadfsimage
> , the 2nd dir will be selected since it has the highest checkpoint time and
> saved to all dirs (including 1st ) .. Now due to this , the new changes b/w
> UPGRADE and ROLLBACK present in 2nd dir gets reflected even after ROLLBACK ..
>
> This is not the case with a SUCCESSFUL Upgrade/Rollback (New changes lost
> after rollback)..
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