[jira] Commented: (HADOOP-1978) Name-node should remove edits.new during startup rather than renaming it to edits.

["dhruba borthakur (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-1978?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12531622 ] 

dhruba borthakur commented on HADOOP-1978:
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This bug was introduced in 0.13. Does it mean that we need a fix for 0.13 release too?

> Name-node should remove edits.new during startup rather than renaming it to edits.
> ----------------------------------------------------------------------------------
>
>                 Key: HADOOP-1978
>                 URL: https://issues.apache.org/jira/browse/HADOOP-1978
>             Project: Hadoop
>          Issue Type: Bug
>          Components: dfs
>    Affects Versions: 0.13.1
>            Reporter: Konstantin Shvachko
>            Priority: Blocker
>             Fix For: 0.14.2, 0.15.0
>
>
> Secondary name-node fails in the middle. The main name-node writes its journal transactions into edits.new at that time.
> If the name-node is shut down after that and restarted, then loadFSImage() reads current image file, merges it with the edits
> file and with the edits.new file.
> Now saveFSImage() saves new image file, creates empty edits file, and then calls rollFSImage(), which particularly renames 
> edits.new into edits. This is a mistake, during startup edits.new should be merely removed after merging it with the image.
> The purpose of calling rollFSImage() during startups imho is to recover from an unsuccessful checkpoint. So an easy fix
> is to empty edits.new before calling rollFSImage the same as edits are emptied, then rollFSImage will rename empty file
> to empty which gives us the desired result.
> We should fix this bug both in 0.14 and 0.15. I make it a blocker for 0.15.

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