[Lustre-discuss] MDS

[Mag Gam]

Brian:

Thanks for the response. I actually seen this response before and was
wondering if my technique would simply work. I guess not.

I guess another question will be, if I take a snapshot every 10 mins
and back it up. If I have a failure at 15th minute. Can I just simply
restore my MDS to the previous snapshot and be with it? Ofcourse I
will lose my 5 minutes of data, correct?

TIA


On Tue, Aug 5, 2008 at 12:08 PM, Brian J. Murrell <Brian.Murrell at sun.com> wrote:
> On Tue, 2008-08-05 at 01:12 -0400, Mag Gam wrote:
>> What is a good MGS/MDT backup strategy if there is one?
>>
>> I was thinking of  mounting the MGS/MDT partition on the MDS as ext3
>> and rsync it every 10 mins to another server. Would this work? What
>> would happen in the 9th minute I lose my MDS, would I still be able to
>> have a good copy? Any thoughts or ideas?
>
> Peter Braam answered a similar question and of course, the answer is in
> the archives.  It was the second google hit on a search for "lustre mds
> backup".  The answer is at:
>
> http://lists.lustre.org/pipermail/lustre-discuss/2006-June/001655.html
>
> Backup of the MDT is also covered in the manual in section 15 at
>
> http://manual.lustre.org/manual/LustreManual16_HTML/BackupAndRestore.html#50544703_pgfId-5529
>
> Now, as for mounting the MDT as ext3 (you should actually use ldiskfs,
> not ext3) every 10 minutes, that means you are going to make your
> filesystem unavailable every 10 minutes as you CANNOT mount the MDT
> partition on more than one machine and we have not tested multiple
> mounting on a single machine with any degree of confidence.
>
> Of course Peter's LVM snapshotting technique will allow you to mount
> snapshots which you can backup as you describe.
>
> But if you are going to have a whole separate machine with enough
> storage to mirror your MDT why not use something more active like DRBD
> and have a fully functional active/passive MDT failover strategy?  While
> nobody in the Lustre Group has done any extensive testing of Lustre on
> DRBD, there have been a number of reports of success with it here on
> this list.
>
> b.
>
>
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