On Tue, 03 Dec 2013 18:13:08 +0100 Oliver Brakmann <oliver brakmann posteo de> wrote: > 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. I would expect that. My setup would be: RAID6 | PV | VG | thin pool Where the RAID6 is provided by a hardware RAID controller with a battery-backed write cache. > > 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. A pity. Thin provisioning would be (as I see it) the first step to whole-VM snapshots as found in systems like VMWare ESX. I'd love to be able to pull that off using Linux/QEMU/KVM. Or at least be able to snapshot a running VM's disk to be able to pull backups off the snapshot without interrupting service in the VM guests.
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