I installed Kubuntu 26.04 using the default ext4 filesystem, but I'm considering switching the boot drive to Btrfs for features like snapshots and automatic deduplication. I've found tools such as btrfs-convert, but I'm worried about data loss and whether they're appropriate for a system that contains the operating system. Is conversion practical, or is backing up, reformatting, and restoring the system the safer approach?
4 Answers
If you created a separate /home partition, you can reinstall the operating system while leaving that partition intact, provided you select the partitions manually and do not format /home. Still back it up first. If /home is part of the same ext4 filesystem as the operating system, you’ll need to copy it elsewhere before reformatting and then restore it.
Btrfs snapshots aren’t automatic just because the filesystem is Btrfs. Useful rollback requires a suitable subvolume layout plus snapshot tools and bootloader integration. Setting that up after installation can be more work than expected, so a distribution or installer that configures snapshots from the start may be a better choice if that feature is your main reason for switching.
btrfs-convert does exist as part of btrfs-progs, and experienced users have used it successfully. However, it’s less straightforward than a fresh filesystem, and you may need to repair or reinstall boot files from a live environment or chroot. Treat it as an advanced recovery-style procedure rather than the normal upgrade path.
The safest and simplest approach is to make a complete, verified backup, format the target filesystem as Btrfs, reinstall the operating system, and restore your personal files. In-place conversion may be possible with btrfs-convert, but it adds complexity and risk, especially on a bootable system. If you use the conversion route, have a working live USB and a tested backup before doing anything.
That’s the distinction I was looking for. So conversion is technically possible, but a clean reinstall is the better-supported option when the goal is a reliable boot setup.