Re: differencing disks support

Dan VerWeire
2011-06-08T20:33:34Z

On Wed, Jun 8, 2011 at 4:09 PM, Iordan Iordanov <iordan@cdf.toronto.edu> wrote:
> Does KVM support or plan to support differencing disks (where there is a
> read-only source disk, and each person running a virtual machine can save
> block-level changes that their virtual machine is making to the disk in a
> separate "differencing" image)?
>
> If so, can somebody suggest how I may make use of this feature (i.e.
> building the newest version from source, and any other requirements).
>
> Thanks!
> Iordan

I believe you could accomplish this with LVM2 snapshots. You would
create an LVM volume with the base install or set of data or whatever.
Then create snapshots of the original volume. Have your guests use the
snapshot volumes.

This page mentions doing it with Xen in the last paragraph:
http://tldp.org/HOWTO/LVM-HOWTO/snapshotintro.html

If you need support in qemu specifically for some reason, that's out
of my realm. Hope this helps though.

Dan VerWeire