NixOS Store Remount

A NixOS module that remounts the Nix store as a writable overlay filesystem and binds /tmp to it — handy for ephemeral systems.

Getting Started

Add this repository as a Nix flake input, then enable the module in your NixOS configuration:

{
  inputs = {
    store-remount.url = "github:ponkila/nixos-store-remount";
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  };

  outputs = { self, ... }@inputs: {
    nixosConfigurations = {
      yourhostname = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = [
          ./configuration.nix
          inputs.store-remount.nixosModules.storeRemount
          {
            # Module configuration
            services.storeRemount = { ... };
          }
        ];
      };
    };
  };
}

Module Configuration

Options

• enable - Enable remounting of the Nix store.
• where - Absolute path of device node, file or other resource.
• type - Filesystem type.
• options - List of options used to mount the file system.

These are comparable to the Where=, Type=, and Options= fields of systemd.mount.

Examples

Dedicated partition

{
  services.storeRemount = {
    enable  = true;
    where   = "/dev/disk/by-uuid/xxxxxxxx";
    type    = "ext4";
    options = [ "noatime" ];
  };
}

Bind under an existing mount

{
  services.storeRemount = {
    enable  = true;
    where   = "/mnt/drive/store";
    type    = "none";
    options = [ "bind" "noatime" ];
  };
}