I don't think preallocation=metadata is required for sparse qcow2. Just if you want it to NOT be sparse for metadata.
I also remember hearing that either recent qemu-img has a decent preallocation by default now, or that performance has improved such that it doesn't matter. Will need to do some reading to remember, but I think I remember hearing it's not a big deal nowadays. On Fri, Jan 31, 2014 at 10:04 PM, Yoshikazu Nojima <m...@ynojima.net> wrote: > Hello Nux, > > Thank you for your comment. I will prepare feature specification. > > Regards, > > 2014-01-31 Nux! <n...@li.nux.ro>: >> On 31.01.2014 20:24, Yoshikazu Nojima wrote: >>> >>> Afternoon All, >>> >>> Is there anyone working on adding volume provisioning method option? >>> As you know, thin provisioning of a volume save consumption of a >>> storage, and fat provisioning improves IOPS performance. >>> Especially, Qcow2 can save storage consumption and achive relatively >>> better performance than default by provisioning a volume with an >>> option "preallocation=metadata", which makes an image file a sparse >>> file. >>> >>> http://itscblog.tamu.edu/improve-disk-io-performance-in-kvm/#.232---preallocation >>> >>> Any thoughts about this? >>> If it is ok, I will write a feature specification on confluence and >>> start implementation. >>> >>> Regards, >>> Noji >>> >>> >>> Yoshikazu Nojima <m...@ynojima.net> >> >> >> Hello, >> >> I thought preallocation=metadata is common practice since years. Now I find >> out ACS doesn't actually use it? >> If so, this is really _bad_ and needs to be fixed ASAP... >> >> Thanks Noji >> >> -- >> Sent from the Delta quadrant using Borg technology! >> >> Nux! >> www.nux.ro
