Re: [ovirt-devel] Unable to import templates

From: "Allon Mureinik" <amureini(a)redhat.com&gt; To: "Christopher Pereira" <kripper(a)imatronix.cl&gt; Cc: devel(a)ovirt.org Sent: Thursday, May 28, 2015 3:31:36 PM Subject: Re: [ovirt-devel] Unable to import templates ----- Original Message ----- > From: "Christopher Pereira" <kripper(a)imatronix.cl&gt; > To: devel(a)ovirt.org > Sent: Tuesday, May 26, 2015 1:44:16 AM > Subject: [ovirt-devel] Unable to import templates > > Hi, > > A user was unable to import a VM template from a gluster export storage > because of various reasons, and since I'm afraid this could hit many > users (losing many days waiting for import tasks to...fail) I would like > to share the issues and some ideas with you: > > 1) Slowness: > > FYI, working with sparse files on GlusterFS mounts will be very slow > until https://bugzilla.redhat.com/show_bug.cgi?id=1220173 is implemented. > Maybe the same applies also to other network file-systems. > > 2) Engine Task timeout: > > The last times the user tried to import this template (using nightly > builds), the task was apparently deleted by Engine because of timeout > while the qemu-img process continued running (and consuming resources). > I'm not sure, but I believe the tasks are deleted by Engine after 4 or 5 > days no matter if the qemu-img process is still running (!?). > Thus, slow import tasks will never finish. > Can someone please confirm? > Maybe we can improve something here to support long import tasks. Sounds like a bug. Could you please report it with all the logs, etc. attached? > > 3) Wrong SPM: > > If $SRC is on host-1, $DST on host-2 and SPM is host-3, the image will > be unnecessarily crossing host-3 and kill the cluster performance. > I guess Engine should choose automatically the appropriate SPM host > depending on the tasks (host-1 or host-2 in this case). > But it seems like oVirt doesn't currently support changing the SPM when > there are running tasks, based on the fact that the user gets a warning > when trying to do it manually. Moving around SPM is WAY too dangerous to do per operation. Looking forward, this should be part of the non-SPM architecture, probably after 3.6.0. > > 4) Convert Optimization: > > I see oVirt is running: > /usr/bin/qemu-img convert -t none -T none -f raw $SRC -O raw $DST > > In this case, $SRC is in raw format and there are no backing chains. > > Shouldn't we do a simple 'cp --sparse=always' instead of a 'qemu-img > convert' in this case? > I guess qemu-img should be doing this optimization for us, but maybe > this raw-to-raw conversion use case is just to silly and will not be > considered by qemu-img maintainers. Definitely worth checking