I don't think there needs to be a lot of engineering around this, we can probably just turn on preallocation=metadata by default.
If there are any other options/features you want to add (such as preallocation=full), they can simply be turned on via agent.properties and/or global/hypervisor/cluster config settings. If you want control for per-disk settings, you'd probably have to add it to disk offerings. I don't really think that's necessary, but some may find it useful. Note that templates are copied in place as-is for qcow2, so however the original template was created will remain intact. However, it's just a backing file so the new qcow2 that stores changes will need to have settings as well. On Fri, Jan 31, 2014 at 11:01 PM, Marcus <shadow...@gmail.com> wrote: > 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
