[
https://issues.apache.org/jira/browse/HDFS-957?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12831526#action_12831526
]
Todd Lipcon commented on HDFS-957:
----------------------------------
Hey Dhruba,
Trailer works too, but that's a file format change. By putting a special value
at the head, then seeking back to replace it with the real layout, we have the
same effect but don't change file format at all.
As for CRC I think that should be done in HDFS-903. I wanted to keep this JIRA
a very small change and leave the big work for 903
> FSImage layout version should be only once file is complete
> -----------------------------------------------------------
>
> Key: HDFS-957
> URL: https://issues.apache.org/jira/browse/HDFS-957
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: name-node
> Affects Versions: 0.22.0
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Attachments: hdfs-957.txt
>
>
> Right now, the FSImage save code writes the LAYOUT_VERSION at the head of the
> file, along with some other headers, and then dumps the directory into the
> file. Instead, it should write a special IMAGE_IN_PROGRESS entry for the
> layout version, dump all of the data, then seek back to the head of the file
> to write the proper LAYOUT_VERSION. This would make it very easy to detect
> the case where the FSImage save got interrupted.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
