I have found a number of old articles on converting to btrfs, several for converting root, but all for other distributions that reference non-fedora things, like not using dracut to rebuild initrd images. I’ve tried several times to convert my VM root disk from ext4 to btrfs, and it all makes sense, but boot stalls and graphical login never arrives. It says “reached multi user target” and many services fail, including DBUG not being able to start on readonly media, then nothing. Virtual consoles never start. Also I cannot boot to single mode, never get root password prompt.
None of this makes any sense. How is rescue mode not working?
Does anyone know of a fedora-focused btrfs conversion cookbook?
Better yet, does anyone know what conditions are required? If I just knew what conditions were necessary I could figure out what to change and how.
- boot install/rescue media – sure, because convert cannot be done on mounted fs.
- convert filesystem with btrfs-convert – obviously required
- update fstab with new UUID & fstyp – makes sense, required
- update grub config (from chroot env) – it is not clear why this is necessary; grub config looks the same to me after doing this. Perhaps this is the problem, but since I don’t know what is supposed to change, I cannot fix it. kernel boot params don’t include root fs type, so…
- (?)rebuild initrd images – it is not clear if or why this is needed, either. Is btrfs not part of initrd img? If not, just rebuilding it will not help anyway, dracut needs to be told to add btrfs, right?
- something else, the above is insufficient.