[Lustre-discuss] MDS

[Mag Gam]

Also, what is the best way to test the backup? Other than really
remove my MGS and restore it. Is there a better way to test this?

TIA


On Tue, Aug 5, 2008 at 6:37 PM, Mag Gam <magawake at gmail.com> wrote:
> 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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>