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+Title: Bikeshedding disk partitioning
+Category: Blog
+Tags: linux, zfs, nixos
+Date: 2019-06-14
+
+I recently got a new Thinkpad. Well...new is a stretch.
+It's an X230, featuring an i5 and 16GB of RAM.
+
+One of the first things I did with this laptopwas to
+[flash coreboot on it](https://octodon.social/users/spacekookie/statuses/10215070602456466)!
+And generally I felt like setting up a laptop in the way I would have always wanted.
+
+And that's where this post begins...
+
+## Encrypted disk
+
+So from the start I knew I wanted to have a fully encrypted disk.
+
+What that means is that your `/boot` partition 
+(whether it is it's own partition or not), is also encrypted.
+
+Secondly, I don't like (U)EFI...
+What that means is that I'm installing GRUB
+in the MBR (with a DOS partition table) instead.
+
+Now: GRUB stage 1 can handle the encryption for us,
+but there's some limitations
+
+- Keyboard layout limited to `US`
+- `/boot` can only be certain partition type
+- `/` and `/boot` need be contained in an LVM
+
+That last one _might_ not be accurate if you only want
+to have an `ext4` (or similar) rootfs. But because I
+want to have a `zfs` root, I need to embed it into an LVM.
+After we've done all this, we will install a linux distribution of choice
+(which we'll talk about later).
+
+Anyway, let's get started!
+
+## Preparing the disk
+
+(Feel free to skip this step)
+
+Something you might want to do is letting your disk look
+otherwise uninitialised, or "securely erasing" any data
+that is already on it.
+But generating random data is a lot of work and `/dev/urandom`
+is very slow.
+
+Instead you can create a crypto-disk (luks) on it, then fill it
+with zero's. But because of the encryption it will seem random.
+
+(/dev/sda is my disk in this example).
+
+```console
+$ cryptsetup luksFormat /dev/sda1
+$ cryptsetup luksOpen /dev/sda sda_crypto
+$ dd if=/dev/zero of=/dev/mapper/sda_crypto bs=512 status=progress
+```
+
+This might take a while, but considerably less time than filling
+the disk with random data. After this is done, you might want to
+actually wipe the first 4096 bytes.
+
+```console
+cryptsetup luksClose sda_crypto
+$ dd if=/dev/urandom of=/dev/sda bs=1M count=8
+```
+
+## Basic partitioning
+
+So what we want to do is setup a single partition on `/dev/sda`,
+the same way we did to prepare the disk. Then repeat the previous
+command to setup a cryptodisk.
+
+What follows is the LVM setup:
+
+```console
+$ pvcreate lvm
+$ vgcreate vg0 /dev/mapper/lvm
+$ lvcreate vg0-boot -l 1G
+$ lvcreate vg0-swap -l 16G
+$ lvcreate vg0-root -L +100%FREE 
+```
+
+Now we want to create the filesystems. 
+For `/boot` we can just use `mkfs.ext4`,
+but consider that I want to use `zfs` on `/`,
+that will require some more work.
+
+```console
+zpool create rtank /dev/mapper/vg0-root # feel free to call your pool whatever!
+
+# At this point you could also create subvolumes for split `/` and `/home` 
+```
+
+## Mounting & Configuration
+
+So that's all good. How do we initialise this system now?
+We need to mount the zfs pool first, then `/boot` and then install
+our linux secret distribution of choice (spoilers: it's [NixOS]!)
+
+[NixOS]: https://nixos.org
+
+```
+mkdir -p /mnt/boot
+zpool import rtank
+mount -t zfs rtank /mnt
+mount /dev/mapper/vg0-boot /mnt/boot
+
+nixos-generate-config --root /mnt
+```
+
+That last line is obviously NixOS specific.
+You now have a fully encrypted disk setup, without
+using EFI. Wuuh!
+
+The rest of this post I want to talk about how to make this
+all work with NixOS and reproducable configuration.
+
+**edit before release**
+
+```nix
+boot.loader.grub = {
+    enable = true;
+    version = 2;
+    efiSupport = false;
+    copyKernels = true;
+    device = "/dev/sda";
+    zfsSupport = true;
+    enableCryptodisk = true;
+};
+boot.zfs.devNodes = "/dev";
+boot.cleanTmpDir = true;
+boot.tmpOnTmpfs = true;
+hardware.cpu.intel.updateMicrocode = true;
+
+fileSystems."/" = {
+    encrypted = {
+        enable = true;
+        label = "lvm";
+        blkDev = "/dev/disk/by-uuid/f1440abd-99e3-46a8-aa36-7824972fee54";
+    };
+    
+networking.hostId = "<random shit>";
+};
+```