I seem to have forgotten to choose "reply all" for this one. So for the sake of completeness my reply again (I now know that there are read-only snapshots):
That command will create a snapshot subvolume and just mount it at the specified directory, correct? I am not such a big fan of this, as the snapshot would then be exposed at file level and I can probably accidentially delete (or modify) those files on the snapshot subvolume making it not a snapshot of a certain point in time anymore? With management of snapshots I did not mean cron (automating stuff), but having an easy and error prone interface for creating and interacting with already created snapshots (like deleting old ones or comparing things). Von: Andrei Borzenkov <[email protected]> Gesendet: Montag, 21. Dezember 2020 19:40 An: Claudius Ellsel <[email protected]>; Roman Mamedov <[email protected]>; Remi Gauvin <[email protected]> Cc: linux-btrfs <[email protected]> Betreff: Re: AW: WG: How to properly setup for snapshots 21.12.2020 21:35, Claudius Ellsel пишет: > I was aware that snapshots are basically subvolumes. Currently I am looking > for an easy way to achieve what I want. I currently just want to be able to > create manual snapshots btrfs subvolume snapshot / /snapshot > and an easy way to restore stuff on file level. cp /snapshot/sub/dir/file /sub/dir/file > For that (including the management of snapshots), snapper seems to be the > best way, as btrfs does not offer such features (in an easy way) out of the > box afaict. Yes, btrfs does not reimplement cron in kernel space. > > Unfortunately the documentation for snapper is also not nice, I just had a > closer look again. The best I could find was the Arch wiki but that also > starts right away with how to create a config (without telling whether that > is even needed for basic usage). > > Ultimately I'd like to have a btrfs Wiki entry for snapshots and am willing > to help with it. > > Von: Andrei Borzenkov <[email protected]> > Gesendet: Montag, 21. Dezember 2020 19:26 > An: Roman Mamedov <[email protected]>; Remi Gauvin <[email protected]> > Cc: Claudius Ellsel <[email protected]>; linux-btrfs > <[email protected]> > Betreff: Re: WG: How to properly setup for snapshots > > 21.12.2020 20:37, Roman Mamedov пишет: >> On Mon, 21 Dec 2020 12:05:37 -0500 >> Remi Gauvin <[email protected]> wrote: >> >>> I suggest making a new Read/Write subvolume to put your snapshots into >>> >>> btrfs subvolume create .my_snapshots >>> btrfs subvolume snapshot -r /mnt_point /mnt_point/.my_snapshots/snapshot1 >> >> It sounds like this could plant a misconception right from the get go. >> >> You don't really put snapshot* "into" a subvolume. Subvolumes do not actually >> contain other subvolumes, since making a snapshot of the "parent" won't >> include any content of the subvolumes with pathnames below it. >> >> As such there's no benefit in storing snapshots "inside" a subvolume. There's > > Having dedicated subvolume containing snapshots makes it easy to switch > your root between subvolumes (either for roll back or transactional > updates or whatever) and retain access to snapshots by simply mounting > containing subvolume. Having them in subdirectory of your (root) > subvolume means you can no more remove this subvolume without also > destroying snapshots before, so you are stuck with it. > > So it makes all sort of sense to think in advance and prepare dedicated > subvolume for this purpose. > >> not much of the "inside". Might as well just create a regular directory for >> that -- and with less potential for confusion. >> >> * - keep in mind that "snapshot" and "subvolume" mean the same thing in >> Btrfs, >> the only difference being that "snapshot"-subvolume started its life as >> being a full copy(-on-write) of some other subvolume. >>
