tech-stuff/Arch linux/Post Wipe.md

Wipe and create LUKS

The keyword being wipe because encryption over a preused partition does not prevent old data from leaking. Kindof scary though to fully wipe your data knowing fully well some subsequent step might ruin most of your baclup. "But I'm too much of a man for external backups...."

• Use fdisk to remove old partitions.
• Create unecrypted boot on /dev/nvmen1p5. (Use mkfs.ext4)
• Create empty partition on remaining space (linux filesystem in fdisk).
• Mount with cryptsetup open --type plain -d /dev/urandom /dev/... to-be-wiped
• dd if=/dev/zero of=/dev/mapper/to-be-wiped bs=1M
• cryptsetup close to-be-wiped
• cryptsetup luksFormat /dev/nvme... (creates luks with a bunch of useful defaults) prompts for passphrase (generate a strong one!)
• Now cryptsetup open /dev/nvme... system which creates /dev/mapper/system
• Finally mount --mkdir /dev/mapper/system /mnt/system

  The final mount will have to be reflected in the fstab and the previous step executed in the initramfs already.

Create btrfs + subvolumes

mkfs.btrfs /mnt/sys I then create 2 subvolumes btfs subvolume create @/ and btrfs subvolume create @rhome

Continue onto Installation