On Mon, Jun 3, 2024, at 3:42 PM, Philip Rhoades via users wrote:
So, if I try to reinstall from the current f40 live usb - can I do that without touching the backup subvolume? ie:
/dev/nvme0n1p3 btrfs 1,951,850,496 464,659,184 1,486,438,224 24% / /dev/nvme0n1p3 btrfs 1,951,850,496 464,659,184 1,486,438,224 24% /backup
Yes. You need to do a custom installation. This is not official documentation, it's intended for Fedora QA purposes, it has macros that show Rawhide versions because - well it's for testing :D so you just stick with the version you have, and adapt it for your usecase.
https://fedoraproject.org/wiki/QA:Testcase_partitioning_custom_btrfs_preserv...
It sounds like you would just create a new root mountpoint, thus a new root subvolume, and not create a /home mountpoint. You can optionally click on the existing backup subvolume and then assign it a mountpoint /backup to have the installer do this for you and add it to fstab. Or you can do it post-install yourself.
Note that unless you explicitly delete the current (broken?) root in the intstaller, it will live on. And you also won't be able to navigate to it from / - you can either mount the top level of the file system and delete it, or you can delete directly by subvolume ID without mounting the top level, see man btrfs subvolume
If you have questions find me (cmurf) on matrix https://matrix.to/#/#fedora:fedoraproject.org