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Re: [Xen-users] Block level domU backup

To: "Nick Anderson" <nick@xxxxxxxxxxxx>
Subject: Re: [Xen-users] Block level domU backup
From: "Agent Rooker" <agentrooker@xxxxxxxxx>
Date: Tue, 28 Oct 2008 15:04:39 -0500
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
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On Tue, Oct 28, 2008 at 1:10 PM, Nick Anderson <nick@xxxxxxxxxxxx> wrote:
>> The idea behind my script is to pause the domU and save a checkpoint
>> file, then create LVM snapshots of the important volumes, then restore
>> the domU.  This would allow me to restore the domU at a later time on
>> another system without losing any data (because uncommitted data would
>> be in RAM).  I understand that this will cause some downtime, but
>> before I thought of this, I was being asked to shut down the domU
>> completely before creating the lvm snapshots.  Anyway, I would like to
>> open this up for comments and criticism.
>
> I had the same idea, however the general consensus on the list seems
> to be that its not safe. I was never able to get a clear answer as to
> how saving the checkpoints did not solve the majority of those issues.
> The one case where I figured there would be a window for corruption
> was if information was coming over the wire that was being written.
>

I should also mention that we're also doing domU level backups with
NetBackup.  So in case something bad happens, the worst thing that
could happen is that we would have to rebuild the system and restore
from one of the backup tapes.  The idea behind this script is to have
a quick and easy failover option in case something bad happens to the
main xen server.

But if someone could make clear the dangers and pitfalls associated
with this plan, that would be very helpful.

-- 
Agent Rooker

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