Migrate Proxmox VE to a custom partition layout feat. Btrfs

proxmox_custom_partition_layout.sh

# The following script was tested for fresh install only, without any VM 
# Assuming Proxmox is installed in /dev/sda with LVM-ext4 partition and UEFI boot, and the target disk is /dev/sdb

# Prepare
sed -i "s/deb/#deb/" /etc/apt/sources.list.d/pve-enterprise.list
apt update
apt full-upgrade -y

# WARNING! Check your target disk device name!
lsblk

# Set up partition table
# Sample layout: 512M ESP partition (same size as Proxmox) + rest as a single Btrfs partition. No swap partition.
(echo g; echo n; echo ''; echo ''; echo '+512M'; echo t; echo 1; echo n; echo ''; echo ''; echo ''; echo w) | fdisk /dev/sdb

# Create boot partition
dd if=/dev/zero of=/dev/sdb1 bs=1M
mkfs.fat -F32 /dev/sdb1

# Create root partition
mkfs.btrfs -f /dev/sdb2
mkdir /mnt/btrfs
mount /dev/sdb2 /mnt/btrfs
rsync -aAXx --numeric-ids --info=progress2 --exclude={"/dev/*","/proc/*","/sys/*","/tmp/*","/run/*","/mnt/*","/media/*","/lost+found"} / /mnt/btrfs 

# Fix boot
# Below is the minimal mounting set for grub-install to work in chroot
for i in /dev /proc /sys; do mount -B $i /mnt/btrfs$i; done
mount /dev/sdb1 /mnt/btrfs/boot/efi
chroot /mnt/btrfs
sed -i 's/GRUB_DISTRIBUTOR="Proxmox Virtual Environment"/GRUB_DISTRIBUTOR="Proxmox Virtual Environment for Btrfs"/g' /etc/default/grub
grub-install /dev/sdb
mkdir /boot/efi/EFI/BOOT
cp /boot/efi/EFI/proxmox/grubx64.efi /boot/efi/EFI/BOOT/BOOTX64.EFI
update-grub

# Fix /etc/fstab
echo "# <file system> <mount point> <type> <options> <dump> <pass>" > /etc/fstab
# Disable fsck for Btrfs. See fsck.btrfs(8).
echo "UUID=`blkid -s UUID -o value /dev/sdb2` / btrfs defaults 0 0" >> root/etc/fstab
echo "UUID=`blkid -s UUID -o value /dev/sdb1` /boot/efi vfat defaults 0 1" >> root/etc/fstab
echo "proc /proc proc defaults 0 0" >> /etc/fstab

# Finish
exit
reboot

# If you need to set up RAID-1 for rootfs, please check
# https://gist.github.com/MakiseKurisu/1b46df3374c1dcbab1048b23312a4e0e