Init bakke (!87)

New backup server just dropped!
This server is awfully slow, and the mdraid setup is awfully slow, and I doubt that this will be a good experience, but we now have a backup server again?

- Tried Disko and nixos-anywhere
- Tried using mdraid
- Found that md is ancient and bad
- Found that disko is 100% extra steps, and a lot more complicated and noisy than just formatting your disks yourself
- Found that systemd-boot doesn't support mdraid
- Found that we probably don't need to mirror the boot partition :)
- Found that old hardware is slow
- Found that old hardware can have poor support for iPXE with UEFI, and might do weird BIOS stuff on you when you least expect it
- Reaffirmed that zfs is love

Current disk layout:
- mdraid for boot/root disk
    - 4TB WD Red with 500MiB ESP with systemd-boot, Remaining mdraid - Old?
    - 4TB WD Red with 500MiB Unused partition, Remaining mdraid - Old?
- zfs pool "tank" for the actual backup data
    - 8TB Toshiba MG08 - New
    - 8TB Exos 7E10 - New

TODO:

- Document the death of Toriel on the wiki
- Document Bakke on the wiki
  - ... describing the poco loco disk layout
- Start backing stuff up
  - Restic? Borg? Rsync?
  - Make backup retention policy and zfs snapshot system
  - Document backup procedures

Reviewed-on: https://git.pvv.ntnu.no/Drift/pvv-nixos-config/pulls/87
Co-authored-by: Felix Albrigtsen <felix@albrigtsen.it>
Co-committed-by: Felix Albrigtsen <felix@albrigtsen.it>

hosts/bakke/filesystems.nix

@@ -0,0 +1,26 @@
+{ config, pkgs, lib, ... }:
+{
+  # Boot drives:
+  boot.swraid.enable = true;
+
+  # ZFS Data pool:
+  environment.systemPackages = with pkgs; [ zfs ];
+  boot = {
+    zfs = {
+      extraPools = [ "tank" ];
+      requestEncryptionCredentials = false;
+    };
+    supportedFilesystems = [ "zfs" ];
+    kernelPackages = config.boot.zfs.package.latestCompatibleLinuxPackages;
+  };
+  services.zfs.autoScrub = {
+    enable = true;
+    interval = "Wed *-*-8..14 00:00:00";
+  };
+
+  # NFS Exports:
+  #TODO
+
+  # NFS Import mounts:
+  #TODO
+}