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From Ravi Prakash <ravihad...@gmail.com>
Subject Re: Hadoop Backup & Restore
Date Tue, 30 Aug 2011 13:01:18 GMT
Hi Avi,

If you restored the metadata from Step 1, it would have no memory of what
happened after that point. I guess you could try using the Offline Image
Viewer and the OfflineEditsViewer tools, to read the corrupted metadata and
see if you can recover the blocks from there.

Cheers
Ravi

On Tue, Aug 30, 2011 at 7:05 AM, Avi Vaknin <avivaknin13@gmail.com> wrote:

> Hi All,
>
> While discussing about Hadoop backup & restore plan with my team I thought
> about a scenario I wanted to ask you about:
>
> I wonder what will happen following the steps below:
>
> 1.       Backup the namenode's metadata (fsimage & edits log).
>
> 2.       Adding files to the Hadoop clutser.
>
> 3.       Deleting files from the Hadoop cluster.
>
> 4.       Corruption in the namenode's metadata or whatever.
>
> 5.       Restoring the namenode's metadata which I backed up (step 1).
>
> How the namenode handle the blocks written or deleted before the corruption
> ?
>
> Will I have access to them ? Is there any procedure I need to do in order
> to
> "fix" the gap created in the time since the last backup?
>
>
>
> Thanks.
>
>
>
> Avi
>
>

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