On 06/19/2018 07:06 PM, Gionatan Danti wrote: > Il 19-06-2018 22:16 Cole Robinson ha scritto: >> Sorry, I misunderstood. You can still achieve what you want but it's >> more clicks: new vm, manage storage, add volume, and select raw volume >> with whatever capacity you want but with 0 allocation. > > Sure, but the automatic disk creation is very handy and much less error > prone. > As it is now, if using a fallocate-less filesystem (eg: ZFS) and *not* > selecting to create a custom disk, you risk waiting minutes or hours for > libvirt to fully allocate the image by writing 0s to the disk file. This > can wreck havok on SSDs and other eundurance-limited medium. > >> qcow2 is the default for virt-manager because it enables features like >> snapshots out of the box. The main motivation I have largely heard for >> wanting raw over qcow2 is performance, but then using sparse raw >> actually makes raw less performant, so it's kind of a weird middle >> ground. For that reason I don't think it warrants adding back the >> checkbox to the new VM UI since I think it's a fairly obscure use case, >> and it can be achieved through the 'manage storage' wizard albeit with >> more clicks >> >> - Cole > > On CoW filesystems, sparse RAW files are faster then Qcow2 ones. > Moreover, avoiding double CoW is important for SSDs (which have limited > lifespan). Even on XFS, sparse RAW files should be faster in the long > run than Qcow2 files, due to no weird limitation on L2 chunk cache size. > > I found the checkbox quite self-explanatory and very handy. Any chances > to reconsider your decision? I see it as another test case and larger UI surface in the common path for something that will save clicks for a corner case. I still don't see it asworth exposing in the UI. - Cole _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
