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Date: Tue, 22 Apr 2008 09:54:39 -0700
From: "Dan Kegel" <dank@kegel.com>
Sender: daniel.r.kegel@gmail.com
Subject: Re: [linux-lvm] Snapshot question...
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On Tue, Apr 22, 2008 at 9:38 AM, Stephane Chazelas
<stephane.chazelas@emerson.com> wrote:
>  actually I've spent the last 3 days trying to put zumastor (well
>  actually ddsnap as I didn't use zumastor in the end) in place
>  here.
>
>  The fact that there are user space daemons involved in the
>  process make it very difficult to use it for the root file
>  system. I had to use a number of hacks for that.

You're braver than us.  We haven't tried using it for the root fs yet.

>  Also, it seems that you can't snapshot a live (mounted) file
>  system as you would do with LVM2 unless you have setup that FS
>  beforehand as a virtual ddsnap device (LVM2 is able to suspend
>  the device, and reload it as a snapshot_origin for that, I
>  couldn't manage to do the same with ddsnap).

Hmm.  I'll bring up that use case with Dan Phillips, see what he says.

>  I also tried applying the patches to 2.6.25 and got some oops
>  (2.6.24.2 is fine though).
>
>  Once I've finalised it, I can post what I've come up with if
>  anyone is interested.

Please do (heck, post it to the zumastor list, too).
- Dan