disko-zfs

Manage your ZFS datasets declaratively

Getting Started

First you have to add this flake as a flake input:

inputs = {
 # other inputs ...
 disko-zfs = {
 url = "github:numtide/disko-zfs";
 inputs.nixpkgs.follows = "nixpkgs";
 inputs.flake-parts.follows = "flake-parts";
 inputs.disko.follows = "disko";
 };
};

Next you need to add the diskoZfs module to your NixOS configuration. How spefically you need to do that is highly dependant, but in the most basic case something like the following should suffice:

{
 inputs = {
 nixpkgs.url = "github:NixOS/nixpkgs?ref=nixos-unstable";
 disko-zfs.url = "github:numtide/disko-zfs";
 };
 outputs = { nixpkgs, disko-zfs, ...}:
 {
 nixosConfigurations.default = nixpkgs.lib.nixosSystem {
 system = "x86_64-linux";
 modules = [
 {
 imports = [
 inputs.disko-zfs.nixosModules.default
 ];
 # your configuration here
 }
 ];
 };
 };
}

With the module in-place, you can use disko-zfs like so:

{
 disko.zfs = {
 enable = true;
 settings = {
 datasets = {
 "zroot/ds1/persist/var/lib/postgresql" = {
 properties."recordsize" = "128K";
 };
 "zroot/ds1/nix" = { };
 "zroot/ds1/home" = { };
 "zroot/ds1/root" = { };
 };
 };
 };
}

Now, when you switch your machine to this configuration, disko-zfs will ensure that the declared datasets along with the declared properties are configured. Any datasets not declared will be left untouched, however disko-zfs will list the commands it would run to destroy any extra datasets.

Note

disko-zfs will NEVER remove any datasets. It will however unset properties, which if they hold unique information could lead to dataloss, you have been warned!

Disko + disko-zfs

If you also utilize Disko in your NixOS configuration, disko-zfs will detect this and automatically include ZFS pools and datasets declared through Disko in its own configuration. As such if you have Disko, you should prefer Disko's way of declaring ZFS datasets and pools. See the ZFS Disko example to get an idea of how to do this.

Dry Running disko-zfs

As a specialty disko-zfs adds an activation script which only executes during dry activation, which will print out the command disko-zfs would run if you were to switch to that NixOS configuration. As such if you run:

nixos-rebuild --flake .#<hostname> --sudo dry-activate

disko-zfs will let you know what it would do.

This project is supported by Numtide.

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