On Tue, Jan 28, 2014 at 06:39:45PM +0000, Martin wrote: > On 27/01/14 18:44, Chris Murphy wrote: > > > > On Jan 27, 2014, at 6:53 AM, KC <impactoria@xxxxxxxxxxxxxx> wrote: > >> > >> 3. If I make a snapshot of / and there are some separate partitions mounted under /mnt/ or /home/, will snapshot skip them? > > > > A snapshot of a subvolume only snapshots that subvolume, not other subvolumes contained in it or other partitions/file systems. > > Thanks. That's a critical detail to know. > > > A few follow-on questions... Are taking snapshots: > > > "atomic"? Yes. The state of the snapshot is that of a single point in the filesystem's history. > Do they hold up or lock out other disk activity? Yes, but only very briefly -- no more than any other simple filesystem operation. > Is there an overhead to keeping many snapshots other than the storage > any changed files take? The storage the changed metadata takes, but that's all. > Can we now consider making and deleting snapshots a "debugged stable > feature"? I think so, yes, although there are still cases where having lots of snapshots (thousands and upwards) can cause problems. I'm thinking specifically of deletion of snapshots, where the system can bog down quite heavily doing all the deletions. Hugo. -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk === PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- Great oxymorons of the world, no. 10: Business Ethics ---
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