postCreateHook = ''
  zfs snapshot zroot/ds1/home@blank';

postCreateHook = ''
  zfs snapshot zroot/ds1/home@blank
'';

I'd like to have this external HDD sometimes plugged in and other times removed, but automatically have LUKS unlocked at boot whenever it's connected. If I remove the disk, the boot process fails at stage 1. Is there a setting I can adjust to fix this apart from mountOptions = ["nofail"]? I'm not too familiar with the initrdUnlock argument: I presume it's what asks for my LUKS password after booting?

      backup_1 = {
        device = hdd_1;
        content = {
          type = "gpt";
          partitions = {
            backup_1 = {
              device = "${hdd_1}-part1";
              priority = 0;
              end = "-0";
              content = {
                type = "luks";
                name = "backup_1";
                initrdUnlock = true;
                extraFormatArgs = ["--pbkdf argon2id"];
                content = {
                  type = "btrfs";
                  extraArgs = ["-f"];
                  mountpoint = "/backup/drive_1";
                  mountOptions = ["compress=zstd" "noatime" "nofail"];
                };
              };
            };
          };
        };
      };