Linux/Btrfs/UbuntuExt4ToBtrfs

2021-02 Ubuntu install cant setup root btrfs.

Install ubuntu from usb, on single /dev/sda2 ext4. (sda1 is efi partition)
Once bootable, boot again from live usb, and convert ext4 to btrfs
- btrfs-convert /dev/sda2

Setup fstab, grub, initram-fs for boot into btrfs

mount /dev/sda2 /mnt
mount -t proc /proc /mnt/proc
mount --rbind /dev /mnt/dev
mount --make-rslave /mnt/dev
mount --rbind /sys /mnt/sys
mount --make-rslave /mnt/ys

chroot /mnt /bin/bash

mount /boot/efi
grub-install /dev/sda
update-initramfs -u
# err fix uuid for / in /etc/fstab
apt install btrfs-tools
update-initramfs -u