{
  config,
  lib,
  pkgs,
  ...
}:
let
  cfg = config.os.srv.replication;
  pgLockScript = pkgs.writeScriptBin "pg-lock" ''
    #!/bin/sh
    microvm -s database-vm -- sudo -u postgres psql -c "SELECT pg_backup_start('sanoid_snap');"
  '';

  pgUnlockScript = pkgs.writeScriptBin "pg-unlock" ''
    #!/bin/sh
    microvm -s database-vm -- sudo -u postgres psql -c "SELECT pg_backup_stop();"
  '';
in
{
  options.os.srv.replication.enable = lib.mkEnableOption "enables replications";
  config = lib.mkIf cfg.enable {
    services = {
      sanoid = {
        enable = true;
        templates.production = {
          autosnap = true;
          autoprune = true;
          hourly = 24;
          daily = 7;
          weekly = 4;
          monthly = 3;
        };
        datasets = {
          "zroot/rpool/appdata/db/postgres" = {
            useTemplate = [ "production" ];

            pre_snapshot_script = "${pgLockScript}/bin/pg-lock";
            post_snapshot_script = "${pgUnlockScript}/bin/pg-unlock";
            no_inconsistent_snapshot = true;
            force_post_snapshot_script = true;
            script_timeout = 30;
          };

          "zroot/rpool/appdata/db/redis".useTemplate = [ "production" ];

          "zroot/rpool/appdata/db/couchdb".useTemplate = [ "production" ];

          "zroot/rpool/appdata/cfg".useTemplate = [ "production" ];

          "zroot/rpool/appdata/games".useTemplate = [ "production" ];

          "zroot/rpool/appdata/mail".useTemplate = [ "production" ];

          "zroot/rpool/containers".useTemplate = [ "production" ];
        };
      };

      syncoid = {
        enable = true;
        commonArgs = [
          "-c"
          "-p"
          "--delete-target-snapshots"
          "--use-hold"
          "--no-sync-snap"
        ];
        commands = {
          "sync-databases" = {
            source = "zroot/rpool/appdata/db";
            target = "tank/ztank/backup/nvme/db";
            recursive = true;
          };

          "sync-config" = {
            source = "zroot/rpool/appdata/cfg";
            target = "tank/ztank/backup/nvme/cfg";
          };

          "sync-games" = {
            source = "zroot/rpool/appdata/games";
            target = "tank/ztank/backup/nvme/games";
          };

          "sync-mail" = {
            source = "zroot/rpool/appdata/mail";
            target = "tank/ztank/backup/nvme/mail";
          };

          "sync-docker" = {
            source = "zroot/rpool/containers";
            target = "tank/ztank/backup/nvme/containers";
          };
        };
      };
    };
  };
}