apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
metadata:
  name: minio-rules
  namespace: storage
spec:
  groups:
    - name: minio.rules
      interval: 15s
      rules:
        - alert: MinIOHighErrorRate
          expr: |
            (
              sum(rate(minio_s3_requests_total{error="true"}[5m]))
              /
              sum(rate(minio_s3_requests_total[5m]))
            ) > 0.05
          for: 10m
          labels:
            severity: warning
          annotations:
            summary: "High error rate on MinIO"
            description: "S3 request error rate exceeded 5% for 10 minutes. Value: {{ $value | humanizePercentage }}"

        - alert: MinIODiskSpaceLow
          expr: |
            (
              minio_cluster_capacity_usable_bytes
              /
              minio_cluster_capacity_raw_total_bytes
            ) < 0.1
          for: 5m
          labels:
            severity: critical
          annotations:
            summary: "MinIO disk space critically low"
            description: "Usable capacity < 10% of raw capacity. Free space: {{ $value | humanizePercentage }}"

        - alert: MinIOReplicationLag
          expr: |
            minio_replication_metrics_replicating_byte_count > 1073741824
          for: 15m
          labels:
            severity: warning
          annotations:
            summary: "MinIO replication lag detected"
            description: "Bytes pending replication > 1GB for 15 minutes. Value: {{ $value | humanize1024 }}B"

        - alert: MinIODriveOffline
          expr: |
            minio_cluster_health_drives_offline > 0
          for: 5m
          labels:
            severity: critical
          annotations:
            summary: "MinIO drive offline"
            description: "{{ $value | humanize }} drive(s) offline in MinIO cluster"