Re: [PATCH v2] docs: expand firmware descriptor to allow flash without NVRAM
On Mon, Jan 31, 2022 at 02:36:46PM +0000, Daniel P. Berrangé wrote:
On Mon, Jan 31, 2022 at 03:00:33PM +0100, Kashyap Chamarthy wrote:
> On Mon, Jan 31, 2022 at 12:55:09PM +0000, Daniel P. Berrangé wrote:
[...]
> I briefly wondered if in this "combined" mode whether
the no. of
> duplicate copies can ever fill up the storage. I doubt that, as the
> combined size of _VARS + _CODE is just about 2MB. So it only starts
> mattering if you're running tens of thousands of guests.
When guest root / data disk sizes are measured in 100's of MB, or
GBs, I struggle to get worried about even a 16 MB OVMF blob being
copied per guest.
Heh, fair enough.
The firmware can be provided in qcow2 format too, so if really
concerned, just create a qcow2 file with a backing store pointing
to the readonly master, so you're only paying the price of the
delta for any guest VARs writes. That's more efficient than what
we do today with copying the separate raw format VARS.fd file.
That's nice, I didn't know the qcow2 possibility in this context. For
some reason I assumed the file format always has to be raw here. Your
qcow2 point above should be documented, if it isn't already. Although
I don't know the right place for it.
[...]
--
/kashyap