On 03/11/2010 08:58 AM, Avi Kivity wrote:
On 03/11/2010 04:19 PM, Anthony Liguori wrote:
But honestly, while I do understand your point, this feels like a hack
to work around shortcomings of an interface. So what we need to decide
is which criterion outweighs the other in practice.
If I understand the use case correctly, what this really boils down
to is that you want to create a growable image on top of a
non-growable device. The management tool then deals with growth
using this interface.
I'm somewhat inclined to suggest that the proper way to support this
is to teach qemu how to grow the LVM volume like it would grow any
normal file.
Interesting. Could use a helper or helper.so, or a new block format
driver (block/lvm.c).
I've suggested plugins for the block drivers in the past. I don't think
it was well received.
Still, if management is actually interested in the change, not just
to grow the volume (perhaps to handle out-of-space, or to check
against a global disk low condition), the helper/driver then needs to
communicate with the management system, which is awkward.
The management system can poll information from the block driver.
Polling is not always evil :-)
Regards,
Anthony Liguori
I guess it's workable though.
