In-Place ext4 to Btrfs Conversion on an Oracle Cloud Ubuntu VM
A writeup of converting an Oracle Cloud Ubuntu 26.04 ARM VM from ext4 to Btrfs in place. WARNING: The operations in this post involve an in-place filesystem conversion — if anything goes wrong, data cannot be recovered. My VM was a blank machine with no important data, which is the only reason I felt comfortable doing this. If your machine has anything you can’t afford to lose, make sure you have a full backup first (Oracle Cloud Boot Volume Backup, rsync to a remote, dd image, etc.), and verify it’s actually restorable before proceeding. A failed filesystem conversion with no backup means total data loss — there’s no undoing it. ...