Fedora xen - May 2006 - Best Practice for backing up running Virtual Machines

On Wednesday 03 May 2006 03:59pm, Christian Reiter
wrote:
> Hello!
>
> I am wondering what''s the best way to backup a running xen-domU.
>
> I''ve just tried to simply copy the file of a file-backed domU
while it
> was running.
> Surprisingly that  was succesful, i didn''t even get a filesystem
error....
That doesn''t surprise me.
>  But i think that is not a reliable way for production servers.
I think you are right about that :) .
> What would you recommend to get reliable disaster recovery backups
> of file-backed as well as partition-backed (raw partition or lvm
> volumes) vms?
I would use LVM to provide the storage and then take a snapshot ("lvcreate 
-s") in dom0 and back that up.
-- 
Lamont R. Peterson <lamont@gurulabs.com>
Senior Instructor
Guru Labs, L.C. [ http://www.GuruLabs.com/ ]
GPG Key fingerprint: F98C E31A 5C4C 834A BCAB  8CB3 F980 6C97 DC0D D409

And how do I manage to take snapshots of VM''s not based on LVM? I mean,
I have 3 VM''s on my System, on three files under a /xenM directory. Is 
there any easy way I can do backups of the running virtual machines?

Thanks a lot!

Lamont R. Peterson escribió:
> On Wednesday 03 May 2006 03:59pm, Christian Reiter wrote:
>   
>> Hello!
>>
>> I am wondering what''s the best way to backup a running
xen-domU.
>>
>> I''ve just tried to simply copy the file of a file-backed domU
while it
>> was running.
>> Surprisingly that  was succesful, i didn''t even get a
filesystem error....
>>     
>
> That doesn''t surprise me.
>
>   
>>  But i think that is not a reliable way for production servers.
>>     
>
> I think you are right about that :) .
>
>   
>> What would you recommend to get reliable disaster recovery backups
>> of file-backed as well as partition-backed (raw partition or lvm
>> volumes) vms?
>>     
>
> I would use LVM to provide the storage and then take a snapshot
("lvcreate
> -s") in dom0 and back that up.
>   
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>
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On Tuesday 16 May 2006 05:30am, Ignacio Verona wrote:
> And how do I manage to take snapshots of VM''s not based on LVM? I
mean,
> I have 3 VM''s on my System, on three files under a /xenM
directory. Is
> there any easy way I can do backups of the running virtual machines?
Convert to using LVM; then it''ll be easy.

Without converting, use backup software designed to deal with active 
filesystems.  That probably means running the backup software underneath of 
each virtual machine.

LVM is a much better choice.  Not just for backups, but it also makes it 
easier to manage your storage.
> Thanks a lot!
HTH.
-- 
Lamont R. Peterson <lamont@gurulabs.com>
Senior Instructor
Guru Labs, L.C. [ http://www.GuruLabs.com/ ]
GPG Key fingerprint: F98C E31A 5C4C 834A BCAB  8CB3 F980 6C97 DC0D D409

On Tuesday 16 May 2006 12:06pm, Ignacio Verona wrote:
> Thanks for your reply Lamont,
>
> unfortunately, there is no easy way I can migrate to LVM my virtual
> machines, as it''s a production server, with no spare partitions
right
> now. Which kind of backup software are you referring to? We have been
> using backup PC for a while, and are pretty happy with that piece of
> software. Will it make the work?
(Please, reply to the whole list.  Thanks :) ).

I haven''t used backup PC, so I can not comment on it.

I was thinking of Amanda (for an open source choice) or TapeWare (looks like 
they changed to name to Backup Standard) [ http://www.yosemitetech.com/ ] for 
the best commercial backup software I have personally used.
-- 
Lamont R. Peterson <lamont@gurulabs.com>
Senior Instructor
Guru Labs, L.C. [ http://www.GuruLabs.com/ ]
GPG Key fingerprint: F98C E31A 5C4C 834A BCAB  8CB3 F980 6C97 DC0D D409

On Tuesday 16 May 2006 12:59pm, Christian Reiter wrote:
> Lamont R. Peterson schrieb:
> > Convert to using LVM; then it''ll be easy.
> > ...
> > LVM is a much better choice.  Not just for backups, but it also makes
it
> > easier to manage your storage.
>
> But bear in mind that LVM-Snapshots aren''t considered reliable at
this
> time.
Where do you get that idea?  What do you mean by, "aren''t
considered
reliable"?

You didn''t think I meant to take a snapshot and call it a day, did you?
No,
absolutely not.  You create a snapshot volume then mount that and back up the 
read only data in it.  The goal is to get a backup you can restore from.

You didn''t think I was talking about using writable snapshots with LVM
for
basing multiple Xen VMs on, did you?  Well, sorry for the confusion it
that''s
the case.  I was talking about read-only LVM snapshot LVs for doing backups.

Hope that clarifies things a bit.
-- 
Lamont R. Peterson <lamont@gurulabs.com>
Senior Instructor
Guru Labs, L.C. [ http://www.GuruLabs.com/ ]
GPG Key fingerprint: F98C E31A 5C4C 834A BCAB  8CB3 F980 6C97 DC0D D409

FWIW, I''ve tried Amanda, and really hated it. It seems to be mature and
well
done, but I was simply unable to contort my mind to think like the Amanda 
developers seem to. As far as I could tell, Bacula is just as powerful and a lot
more understandable. At least, that''s how it struck me.

On Tue, 16 May 2006, Lamont R. Peterson wrote:
> On Tuesday 16 May 2006 12:06pm, Ignacio Verona wrote:
>> Thanks for your reply Lamont,
>>
>> unfortunately, there is no easy way I can migrate to LVM my virtual
>> machines, as it''s a production server, with no spare
partitions right
>> now. Which kind of backup software are you referring to? We have been
>> using backup PC for a while, and are pretty happy with that piece of
>> software. Will it make the work?
>
> (Please, reply to the whole list.  Thanks :) ).
>
> I haven''t used backup PC, so I can not comment on it.
>
> I was thinking of Amanda (for an open source choice) or TapeWare (looks
like
> they changed to name to Backup Standard) [ http://www.yosemitetech.com/ ]
for
> the best commercial backup software I have personally used.
> -- 
> Lamont R. Peterson <lamont@gurulabs.com>
> Senior Instructor
> Guru Labs, L.C. [ http://www.GuruLabs.com/ ]
> GPG Key fingerprint: F98C E31A 5C4C 834A BCAB  8CB3 F980 6C97 DC0D D409
>

Does any body know why "xm save" doesn''t work? that will be
the easiest
way of taking snapshots of running virtual machines. I hope that works 
on future versions of Xen...