{config,...}:

# to use this, you must have created the lvm devices for the host
# in this example, my hostname is sobble and the disk is /dev/sda:
# 
#     fdisk /dev/sda
#     n  # new partition, assuming this is a blank disk.
#        #     (enter for all defauls until you're back at the prompt)
#     t  # set type
#     1  # first partition, again assuming this was a blank disk
#     8e # lvm
#     w  # write and quit
#     
#     either make the lv inside an existing vg like the root luks one
#     ----------
#     lvcreate -L50G -n sobble-tank-nvme sobble-luks
#     --- or ---
#     pvcreate /dev/nvme0n2p15
#     vgcreate sobble-tank-nvme /dev/nvme0n2p15
#     lvcreate -l 100%FREE -n sobble-tank-nvme sobble-tank-nvme
#     -- then --
#     mkfs.ext4 /dev/sobble-tank-nvme/sobble-tank-nvme

let
m = "${config.networking.hostName}-luks";
n = "${config.networking.hostName}-tank-nvme";
in
{
  fileSystems."/tank/nvme" = {
    device = "/dev/${m}/${n}";
    fsType = "ext4";
  };
}