[linux-lvm] lvm over loop device

Bryn M. Reeves bmr at redhat.com
Mon Sep 29 09:08:40 UTC 2008

Hash: SHA1

geert Geurts wrote:
> So what I did first create a LVM partition of 1MB on a memorystick and then 
> change the if of dd to point to the LVM partition, I'm now able to pvcreate 
> /dev/loop0, vgcreate SmallDisk /dev/loop0.
> But I'm unable to create a logical volume in the SmallDisk group...
> what am I doing wrong here? is it even possible if not why?

Hi Geert,

What was the error you were getting at this point? If possible, can you
use a service like pastebin.com to post the complete output of "lvcreate
- -vvv" with the options you're using for the SmallDisk VG. That should
give enough detail to have some idea where it's failing.

I think the idea is reasonable enough although you'll probably need to
do some fiddling around to get the size/number of the gmailfs volumes
right to give good performance.

Snapshots could definitely work here but I think it might be a bit
tricky without some of the patches that are currently outstanding for
device-mapper, esp. Mikulas' snapshot merging patches which you'd need
to "restore" one of the COW areas. See the thread here:



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