So I installed Debian 12 with btrfs and apparently it only uses a single subvolume rootfs
. I would like to have my /home
in a separate subvolume (and possibly /var
too I guess) and with a flat subvolume structure. I started figuring out on how to do it and I feel like I’m not entirely sure yet so I need a sanity check.
Lots of comments online seem to use something like this method:
cd /
mv /home /home_old
btrfs subvolume create home
cp -a --reflink=always /home_old/* /home/
But this would NOT create a flat subvolume structure, right? And you woul NOT need to modify fstab
as the /home
would be automatically mounted because it resides under rootfs
actually because /
is rootfs
and not its parent?
If I want to actually have a flat structure, then I would first need to mount the actual parent subvolume (subvolumeid=5), cd into it, then create the home
subvolume, copy everything from the current home
directory into there, unmount, modify fstab
to mount home
, and delete the old stuff and reboot I guess.
Soo something like this:
mkdir /mnt/tmp
Make a folder for mount
mount -o subvolid=5 /dev/sdXX /mnt/tmp/
Mount the actual parent subvolume
cd /mnt/tmp/
Here 'ls -a' would output 'rootfs' if I understood correctly
btrfs subvolume create home
Create new subvolume, now being sibling of 'rootfs'
cp -a --reflink=always /home/* /mnt/tmp/home/
Copy old /home
umount /mnt/tmp/
Don't need it anymore
Then go to fstab
, and do something like
...
UUID= / btrfs subvol=rootfs bunch_of_options_and_stuff
...
-> change into
...
UUID= / btrfs subvol=rootfs bunch_of_options_and_stuff
UUID= /home btrfs subvol=home bunch_of_options_and_stuff
...
Then just rm -rf /home/
(or just move to keep it as backup if something is fucked up) and reboot?
Does this sound about right?
[This comment has been deleted by an automated system]
I still don’t see how having a flat subvolume layout would make that more problematic. You can still (even better in my opinion) choose what subvolumes to automatically snapshot, which to include in backups etc.
[This comment has been deleted by an automated system]