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From "Doug Cutting (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-1978) Name-node should remove edits.new during startup rather than renaming it to edits.
Date Mon, 01 Oct 2007 20:39:50 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-1978?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12531626

Doug Cutting commented on HADOOP-1978:

> Does it mean that we need a fix for 0.13 release too?

I don't think so.  Folks can upgrade from 0.13 to 0.14.2 to get this fix.

> 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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