On 11/3/2014 8:43 AM, Andrey Korolyov wrote:
On Mon, Nov 3, 2014 at 4:24 PM, Michal Privoznik <mprivozn@redhat.com> wrote:
On 01.11.2014 05:30, Dennis Jacobfeuerborn wrote:
Hi, I'm trying to find out how to enable fstrim support for libvirt/qemu guests. Specifically I'm trying to enable this on a CentOS 7 host (qemu 1.5). I searched the web but only found very vague information and no clear documentation on the requirements or how to modify the guest xml to enable discard/fstrim support.
Can someone point me in the right direction?
One thing that you'll need is the guest agent:
http://wiki.libvirt.org/page/Qemu_guest_agent
Then you can just use:
# virsh domfstrim $dom
Michal ... and probably discard-aware block driver (although I cannot name anything except virtio-blk which is not supporting trim or will not support in the near future). Not sure to which part, guest-host interaction or driver abilities, the initial question belongs.
The virtio-scsi driver supports it, though you take a minor performance hit for switching.