Surprisingly, very little work needed.
The June 2015 release was a no-go because I couldn’t get initramfs booted (and I didn’t want to start tearing apart the boot files or compiling the kernel myself).
Updated to the latest version. Only the standard set of changes needed to get BTRFS running (along the same line that I needed to perform on a raspbian install).
In a nutshell:
- apt-get install btrfs-tools
- add btrfs to /etc/initramfs-tools/modules
- update-initramfs -c -k
uname -r - for the initramfs image generated (4.4xyz etc), add following to /boot/config.txt
initramfs initrd.img-…4.4xyz… followkernel - modify /boot/cmdline.txt
rootfstype=btrfs
root=/dev/…btrfs_partition…
rootflags=subvol=…subvolume_name… - create a btrfs partition (/dev/…btrfs_partition…) and rsync a copy of root to subvolume …subvolume_name…
- update /etc/fstab in subvolume …subvolume_name to reflect correct mounting for btrfs (type, subvol, etc)
- relocate swap to a ext4 partition (modify the perform_tuner script in /usr/sbin/ to replace /swap with path to swap file)
…
reboot and be greeted with the “Scanning for BTRFS filesystems…”
Absolutely painless to migrate.