Re: [libvirt-users] libvirt, lvm thin provisioning

Oliver Brakmann
Tue, 03 Dec 2013 17:13:08 -0000

Hello,

On 2013-11-22 21:46, Michael Mol wrote:
> I know that lvm supports thin provisioning, and I think I have a pretty
> good grasp on how that works. Does libvirt support lvm thin
> provisioning and thin snapshots?

libvirt does not support storage pools containing thin pools.  Since
commit 4132dede0652b7f0cc83868fd454423310bc1a9c
(http://libvirt.org/git/?p=libvirt.git;a=commit;h=4132dede0652b7f0cc83868fd454423310bc1a9c)
at least the thick provisioned volumes in such a pool can still be used.
Previously, libvirt would just refuse to start the pool.

However, you can assign any thin provisioned volume to a VM manually and
it will work.  On the hardware/software combination that I tried it on
(desktop SATA drives in RAID1 on Ubuntu 13.10) it was abysmally slow though.

Proper support for LVM thin provisioning would probably need a new
storage pool type, and I haven't found any hints that anybody was
working on that.


Greetings
Oliver