Convert a rootfilesystem of a Raspberry from ext4 to btrfs

Details: Category: Raspberry; Also available:; Created: 08 January 2025; Last Updated: 20 January 2025; Hits: 2200

btrfs has some nice features. That's why it makes sense to convert the root filesystem of a Raspberry running RaspbianOS from ext4 to btrfs.

Note: The following instructions require basic Linux knowledge because it's just a memory aid for me and the instructions are not very detailed.

Update the system

sudo apt-get update
sudo apt-get upgrade

Install required tools

sudo apt-get install btrfs-tools initramfs-tools

Add btrfs to initramfs modules

echo 'btrfs' | sudo tee -a /etc/initramfs-tools/modules

Initramfs updaten

sudo update-initramfs -c -k $(uname -r)

Reboot und check dass btrfs unterstützt wird
```
dmesg | grep -i btrfs
```
Optional: Backup your system
Boot the seconds RaspbianOS with the same kernel level and attach the SD card with the system to convert

Check filesystem for errors

sudo fsck.ext4 /dev/<zu konvertierende partition>

Convert the ext4 filesystem to btrfs

sudo btrfs-convert /dev/<zu konvertierende partition>

Update cmdline.txt with the UUID of the new root filesystem and update the filesystem used from ext4 to btrfs. Use follwoing command to retrieve the required informatio
```
lsblk -fs
```
Update /etc/fstab with zje UUIDs of the boot and root partition and update the filesystem used from ext4 to btrfs
Boot the converted system and enjoy the btrfs features