Hello Anonnymous, cc:kvm
On Friday 28 October 2011 04:48:57 day knight wrote:
> I am using ext3 and your explaination makes sense. May I also ask if
> the qcow image automatically adjusts to the size or is it ever
> expanding image?
That depends: Originally Qcow2 only expands, since Qemu/kvm doesn't know
what's inside your image file, that is if and what file systems it contains
and how they're structured. Because of that it can't know which blocks are
free and which are still used.
Since qemu/kvm-0.15 there is TRIM support (which originally was developed for
flash-storage media), which — I think — is also supported for Qcow2. If your
Guest-OS supports TRIM, it can tell the underlaying storage media — Qcow2 —
that blocks are now unused, which Qemu/kvm can then free.
> I mean lets say I have 100 Gig and write 20 Gig on
> qcow ext3 image and then delete 10 Gig data. Would it show up as
> 120Gig or 110 once the deletion is done
Sincerely
Philipp
--
Philipp Hahn Open Source Software Engineer hahn@xxxxxxxxxxxxx
Univention GmbH Linux for Your Business fon: +49 421 22 232- 0
Mary-Somerville-Str.1 D-28359 Bremen fax: +49 421 22 232-99
http://www.univention.de/
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