Fstab & BTRFS / snapper snapshots issue

Today I was tinkering around with a second install on an external drive.
Not using EndeavourOS, but an Arch install via the nwg-iso which is shipping with sway… btw.

Anyway. Something didn’t really worked out in the process of setting up snapper & btrfs-assistant.
I wasn’t able to create a new ‘.snapshots’ subvolume as it already existed, thus I had to unmount in order to delete & create a new one via btrfs assistant. This worked, but the system now fails to boot as .snapshots couldn’t be mounted anymore.

I guess that it’s pretty much due to the reason that there is still an entry in /etc/fstab which is mounting that btrfs subvolume ? Should I simply remove it ?

Just trying to understand this. In comparison to my main install here. Which is also working with snapper and btrfs assistant & grub-btrfs - there isn’t an entry within the fstab.

I’d try commenting it out rather than just removing it.

Btrfs once had a wiki for documentation which provided a great section for that, but it seems they got rid of the wiki. Alas poor Yorik. But it comes down to how to organize subvolumes: “flat” vs “nested”.

Flat usually means branches from the root subvolume. These you would mount in fstab to the right place.

Nested means you just put down a subvolume in a directory and it is automatically mounted in place with the subvolume “above” it.

Snapper usually creates a nested subvolume in the right place and there is no need to mount it manually in the fstab. If there is still a dedicated but unavailable “snapshot” volume in the fstab that is probably the reason for the boot failure.

Disclaimer: That assessment made without any actual logs, cmds, configs etc. provided.

Which is what I did… and the external install boots again. But there is still something fishy, the pacman hook isn’t working as expected.

(1/2) Making BTRFS snapshot…
There are no old snapshots to be deleted!
Error while creating snapshot arch-x7qsl1!
Error while creating snapshot vmail-bbdqk1!
Error while creating snapshot nextcloud-wodlif!

friese@swarchy /> cd usr/share/libalpm/hooks/
friese@swarchy /u/s/l/hooks> ls -l
total 152
-rw-r–r-- 1 root root 244 Aug 3 19:33 01-btrfs-autosnap.hook
-rw-r–r-- 1 root root 1107 Jul 1 2024 05-snap-pac-pre.hook
-rw-r–r-- 1 root root 1057 Jul 1 2024 10-snap-pac-removal.hook

Ah, that was easy to fix. The 01-btrfs-autosnap.hook is redundant, 05-snap-pac-pre.hook does the job just fine and 10-snap-pac-removal.hook solely exists for the removal of snap-pac itself.

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