Re: [libvirt] Changing the default for qcow2 creation
Hello,
Am Dienstag 02 November 2010 23:45:59 schrieb Eric Blake:
On 10/25/2010 08:06 AM, Richard W.M. Jones wrote:
>> libvirt's qemu driver doesn't currently preallocate qcow2 metadata
>> when creating a new image. Given the tiny disk space overhead of the
>> metadata (0.02%) and the small processing overhead of pre-creation
>> relative to subsequent creation on-the-fly, I suggest that the
>> libvirt qemu driver is updated to pre-allocate metadata by default.
...
Is this something that we should just globally enable if qemu
supports
it, or do we need some XML tunable to allow someone to skip the
pre-allocation for some reason?
I don't know if its relevant, but if you create a qcow2 image, which is based
on another base-image, you must not pass the option to pre-allocate, else you
get the following error message:
Backing file and preallocation cannot be used at the same time
Sincerely
Philipp Hahn
--
Philipp Hahn Open Source Software Engineer hahn(a)univention.de
Univention GmbH Linux for Your Business fon: +49 421 22 232- 0
Mary-Somerville-Str.1 28359 Bremen fax: +49 421 22 232-99
http://www.univention.de
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