FYI btrfs quotas are not yet "stable" even in the newest kernel (4.11.x as we speak).
Reference: https://btrfs.wiki.kernel.org/index.php/Status There are also btrfs quota problems mentioned on btrfs mailing lists quite often (severe performance problems, inaccurate or even negative counts, especially when snapshots are in use; kernel crashes/stability issues). So making LXD enable it automatically might be premature - btrfs quotas might work in two or five years from now, but they are not there yet. If LXD wants to support it - fine; but IMO don't enable it by default, add a big fat warning for the user about the potential issues and document a way to enable it manually. Tomasz Chmielewski https://lxadm.com On Monday, June 05, 2017 02:11 JST, Stéphane Graber <[email protected]> wrote: > On Sun, Jun 04, 2017 at 08:36:28AM -0400, Ron Kelley wrote: > > Greetings all. > > > > I recently upgraded a number of LXD 2.08 servers to 2.12 and noticed the > > btrfs “quota” option was enabled where it was disabled before. Enabling > > quotas on a filesystem with lots of snapshots can cause huge performance > > issues (as indicated by our 20min outage this morning when I tried to clear > > out some old snapshots). > > > > Can one of the developers confirm if the upgrade enables quota? If so, I > > will file a bug to ensure the user gets notified/alerted quotas will be > > enabled (so it can be disabled if necessary). > > > > -Ron > > LXD enables btrfs quota on any newly created btrfs pool, which includes > all your existing ones when upgrading to LXD 2.9 or higher (as the > upgrade step effectively creates a new pool). > > That's done so that the size limit feature of LXD can work on btrfs. > > > Given the potential performance impact and the fact that btrfs quotas > aren't that great to begin with, I'd be fine with adding a pool > configuration option that lets you turn them off. And tweaking our > upgrade code to set that property based on the existing state. > > > Filing a github issue would be good. Please include what I wrote above > and I suspect Christian will take a look into this shortly. > > -- > Stéphane Graber > Ubuntu developer > http://www.ubuntu.com _______________________________________________ lxc-users mailing list [email protected] http://lists.linuxcontainers.org/listinfo/lxc-users
