On 2015-07-20 T 16:51 -0600 Chris Murphy wrote:
On Mon, Jul 20, 2015 Matthias G. Eckermann wrote:
Am 20. Juli 2015 20:20:36 MESZ, schrieb Chris Murphy:
On Mon, Jul 20, 2015 at 11:13 AM, Matthias G. Eckermann wrote:
And with respect to the number of snapshots: size is the limit.
In theory that's true, in practice Btrfs itself has problems with many snapshots at the moment irrespective of available free space in the volume.
my experience with btrfs is different in the positive way.
Can you point us to SUSE bugreports indicating the opposite?
No, that information is on the upstream linux-btrfs@ list. It's come up several times, in particular when deleting many snapshots because the metadata for all extents involved must be visited and rewritten so a lot of deletion can cause a lot of writing.
While this is true, it does not limit the number of snapshots. It only determines the time to delete snapshots (which is a different question).
On of the more well knowns cases is with VM images and databasess, even when not snapshotting and even when using chattr +C.
That is a different question than the _number_ of snapshots, and frankly, the same is true for all CoW filesystems (including for example ZFS).
vmm-libvirt places its images in /var/lib/libvirt/images and isn't excluded from snapper, so that's a problem source. But snapshotting makes the problem worse, quickly. http://www.spinics.net/lists/linux-btrfs/msg40563.html
As far as I am aware, VM images under /var/lib/libvirt are automatically created with NoCOW on openSUSE (>13.1) and SUSE Linux Enterprise 12 systems. Please check. If this is not the case, it's worth a bug report. So logn - MgE -- Matthias G. Eckermann - Senior Product Manager SUSE® Linux Enterprise Phone: +49 30 44315731 Mobile/DE: +49 179 2949448 SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Dilip Upmanyu, Graham Norton, HRB 21284 (AG Nürnberg) -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org