USB storage devices

Auto-mounting with udisks

udiskie, a udisks2 front-end that allows to manage removable media can be used. To enable automounting, first enable udisks2:

❄︎ /etc/nixos/configuration.nix

services.udisks2.enable = true;

Next enable udiskie via Home Manager:

❄︎ ~/.config/home-manager/home.nix

services.udiskie = {
    enable = true;
    settings = {
        # workaround for
        # https://github.com/nix-community/home-manager/issues/632
        program_options = {
            # replace with your favorite file manager
            file_manager = "${pkgs.nemo-with-extensions}/bin/nemo";
        };
    };
};

Once the configurations are reflected, USB storage devices will be instantly recognized when inserted without any additional operations needed.

Mounting at boot

Troubleshooting

While booting you might get a timeout error, caused by missing kernel modules in your initrd. Error message: [ TIME ] Timed out waiting for device /dev/disk/by-partlabel/disk-<name>-<partition>

To fix this simply add the missing kernel module to your initrd.

❄︎ /etc/nixos/configuration.nix

{
  boot.initrd.availableKernelModules = [
    "uas" # USB Attached SCSI driver
  ];
}

You can find the missing kernel modules by plugging in your external storage device and comparing the outputs of the following two commands:

# Modules available on booted system: 
lsmod

# Modules available at boot:
nix eval --file '<nixpkgs/nixos>' -A config.boot.initrd.availableKernelModules

For other solutions, please refer to udisks - ArchWiki or USB storage devices - ArchWiki.