[linux-lvm] Snapshots and disk re-use

[James Hawtin]

On 05/04/2011 20:48, Jonathan Tripathy wrote:
>
> Yeah, I'll have to try this on a non-production server. Which kernel 
> do you expect to crash? The Dom0 (Xen + LVM host) or the VM? Anyway, 
> just thinking about it, it seems that pausing/saving/shutting down the 
> VM is a must, as the VM may be writing to disk at the time of zeroing 
> the cow (!!).
>
> In the hosting industy, what does everyone else do? Do they just 
> ignore the issue???
>
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As an alturnative could you not?

1) Create snapshot lv using specific physical extents.
lvcreate -s -l 100 ..... /dev/sdx1:0-99
2) Backup VM
3) Delete snapshot lv
4) create a normal lv using same physical extents
lvcreate -l 100 ..... /dev/sdx1:0-99
5) zero normal lv
6) delete normal lv

James