On Wed, 2017-11-01 at 19:17 +0800, Qu Wenruo wrote: > > On 2017年11月01日 19:04, ST wrote: > > Hello, > > > > I read in different places that one should keep amount of snapshots low > > - around 15-20. My question - is this limitation on total number of > > snapshots on the system or only on related (parent<->child) chain of > > snapshots? > > Independent subvolume doesn't count, and it's filesystem based. > > So only snapshots (with source exists, and still shares a lot of trees > with source) counts. > > And if you have multiple btrfs fses, then the count should be based on > each fs. > > > What I want to do is the following: create (and then rotate) last 7 > > daily snapshots (and maybe 4 weekly) for each user in his /home dir. > > For > > around 100 users. So if limitation is only on related snapshots then I'm > > OK since only each 7 (or maybe 7+4) of them are related which is well > > under the 15-20 limit. However in total there could be 700 snapshots. So > > what is true? > > You're OK since independent subvolumes won't cause too much stress for > backref walk. > > The only thing you may need to consider is to limit the ability to > reflink data between subvolumes. > Like cp --reflink or even offline dedupe. Thank you very much! How can I limit this ability? (I'm on Debian9) All the best! -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
