On Oct 15, 2013, at 4:29 PM, Richard W.M. Jones <rjones@xxxxxxxxxx> wrote: > On Tue, Oct 15, 2013 at 04:04:28PM -0600, Chris Murphy wrote: >> I'm happy to hear it argued I should instead use the LV space for a >> regular partition formatted ext2 and drop the qcow2 file >> there. There's still overhead of two file systems there, but may >> compare to LV performance. > > I guess you'll have to try that and see how it works out. > > However don't use ext2. Use ext4 which supports extents and hence > will have much lower metadata over for big files like disk images. Fair point. The system I have, has a disk with both XFS formatted partition (no LVM) and LVM space on it. Fedora 20 default BTRFS guided install to an LV takes 51 minutes. Firstboot systemd-analyze: 878ms (kernel) + 2.755s (initrd) + 24.796s (userspace) = 28.429s The same install parameters to qcow2 on XFS takes 1h42m. Firstboot systemd-analyze: 876ms (kernel) + 3.065s (initrd) + 31.858s (userspace) = 35.799s Boot difference is negligible, but the installation time difference is quite large, so it looks like write performance is where the penalty is. I'd be surprised if there's a significant difference with qcow2 on ext4. Chris Murphy -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
