Not having snapshots on ext4 finally got too annoying. I was able to copy the root filesystem off, then format with btrfs and copy it back on. I used System Rescue CD to do this, turn off Copy on Write on database files, and edit /etc/fstab with the new filesystem and UUIDs. It worked! Eventually. There were a few snags:
- Grub gets angry when you wipe all your partitions. I’m still not clear on what the UUID it was looking for was, because it didn’t look like the old root filesystem. Using System Rescue CD’s Super Grub Disc image I was able to boot into the system and run update-grub and install-grub, which fixed it.
- tar with bzip2 is slow. Using tar without compression ended up being much, much faster.
- Taking out the drive with the swap partition caused the boot to hang until timeout. There isn’t an mkfs.swap, but there is a mkswap.
- The script I used to disable CoW didn’t preserve ownership information, so I had to re-chown things appropriately. Oddly PostgreSQL still started, but MySQL did not. That was nice because it alerted me to the problem.
Hooray for snapshots! I’m hoping to set up snapshot backups Soon. (TM)