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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 Gesendet: Montag, 21. Dezember 2020 19:40 An: Claudius Ellsel ; Roman Mamedov ; Remi Gauvin Cc: linux-btrfs Betreff: Re: AW: WG: How to properly setup for snapshots š 21.12.2020 21:35, Claudius Ellsel ÐÉÛÅÔ: > 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 > Gesendet: Montag, 21. Dezember 2020 19:26 > An: Roman Mamedov ; Remi Gauvin > Cc: Claudius Ellsel ; linux-btrfs > Betreff: Re: WG: How to properly setup for snapshots > š > 21.12.2020 20:37, Roman Mamedov ÐÉÛÅÔ: >> On Mon, 21 Dec 2020 12:05:37 -0500 >> Remi Gauvin 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, >> šššš the only difference being that "snapshot"-subvolume started its life as >> šššš being a full copy(-on-write) of some other subvolume. >>