{ lib, pkgs, config, ... }:
{
  grafanaAlertRuleDefinitions = [
    # RAID array degraded - critical
    {
      uid = "raid-array-degraded-uid";
      title = "RaidArrayDegraded";
      condition = "D";
      data = [
        {
          refId = "A";
          datasourceUid = "vm-datasource-uid";
          relativeTimeRange = { from = 300; to = 0; };
          model = {
            expr = ''mdadm_array_state == 0'';
            instant = false;
          };
        }
        {
          refId = "C";
          datasourceUid = "__expr__";
          model = {
            type = "reduce";
            expression = "A";
            reducer = "last";
          };
        }
        {
          refId = "D";
          datasourceUid = "__expr__";
          model = {
            type = "math";
            expression = "$C == 0";
          };
        }
      ];
      for = "0s";
      noDataState = "NoData";
      execErrState = "Error";
      annotations = {
        summary = "RAID array {{ $labels.array }} is degraded";
        description = ''
          RAID array {{ $labels.array }} on {{ $labels.instance }} is in state "{{ $labels.state }}".
          The array is not in a healthy state. Check for failed disks immediately!
        '';
      };
      labels = {
        severity = "critical";
        category = "storage";
      };
    }

    # RAID missing devices - critical
    {
      uid = "raid-missing-devices-uid";
      title = "RaidMissingDevices";
      condition = "D";
      data = [
        {
          refId = "A";
          datasourceUid = "vm-datasource-uid";
          relativeTimeRange = { from = 300; to = 0; };
          model = {
            expr = ''mdadm_array_devices_active < mdadm_array_devices_total'';
            instant = false;
          };
        }
        {
          refId = "C";
          datasourceUid = "__expr__";
          model = {
            type = "reduce";
            expression = "A";
            reducer = "last";
          };
        }
        {
          refId = "D";
          datasourceUid = "__expr__";
          model = {
            type = "math";
            expression = "$C > 0";
          };
        }
      ];
      for = "0s";
      noDataState = "NoData";
      execErrState = "Error";
      annotations = {
        summary = "RAID array {{ $labels.array }} has missing devices";
        description = ''
          RAID array {{ $labels.array }} on {{ $labels.instance }} has fewer active devices than expected.
          A disk may have failed or been removed. Check array status immediately!
        '';
      };
      labels = {
        severity = "critical";
        category = "storage";
      };
    }
  ];
}