Re: [ovirt-devel] Unable to import templates

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.

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.

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.

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