{
  "docVersion": 1,
  "id": "blog-dr-t2",
  "name": "Tier 2 — Pilot Light",
  "purpose": "The database geo-replica stays on and current in region B; the app tier is defined but scaled to zero. Failover scales it up and Front Door reroutes.",
  "nodes": {
    "fd": {
      "type": "gateway",
      "label": "Azure Front Door",
      "x": 380,
      "y": 20,
      "w": 138,
      "h": 84,
      "runtime": "global entry · health probes"
    },
    "app": {
      "type": "k8s",
      "label": "App Service",
      "x": 60,
      "y": 180,
      "w": 138,
      "h": 84,
      "color": "green",
      "runtime": "primary · full"
    },
    "db": {
      "type": "database",
      "label": "Azure SQL DB",
      "x": 60,
      "y": 340,
      "w": 138,
      "h": 84,
      "color": "green",
      "runtime": "primary"
    },
    "rdb": {
      "type": "database",
      "label": "SQL geo-replica",
      "x": 720,
      "y": 180,
      "w": 138,
      "h": 84,
      "color": "amber",
      "runtime": "region B · ON, small"
    },
    "rapp": {
      "type": "k8s",
      "label": "App Service",
      "x": 720,
      "y": 340,
      "w": 138,
      "h": 84,
      "style": "dashed",
      "runtime": "region B · scaled to 0"
    }
  },
  "edges": {
    "e0": {
      "from": "fd",
      "to": "app",
      "fromSide": "left",
      "toSide": "top",
      "label": "all traffic",
      "color": "green",
      "animated": true
    },
    "e1": {
      "from": "db",
      "to": "rdb",
      "fromSide": "right",
      "toSide": "left",
      "label": "active geo-replication",
      "style": "dashed",
      "animated": true
    },
    "e2": {
      "from": "rdb",
      "to": "rapp",
      "fromSide": "bottom",
      "toSide": "top",
      "label": "scale up on failover",
      "color": "amber",
      "style": "dashed"
    },
    "e3": {
      "from": "fd",
      "to": "rapp",
      "fromSide": "right",
      "toSide": "top",
      "label": "reroute on failover",
      "color": "amber",
      "style": "dashed"
    }
  },
  "boxes": {
    "z1": {
      "x": 30,
      "y": 120,
      "w": 240,
      "h": 340,
      "label": "region A — primary",
      "color": "green",
      "opacity": 0.04
    },
    "z2": {
      "x": 690,
      "y": 120,
      "w": 240,
      "h": 340,
      "label": "region B — pilot light",
      "color": "amber",
      "opacity": 0.04
    }
  },
  "texts": {
    "t1": {
      "x": 30,
      "y": 480,
      "text": "RTO: ~10–30 min (data's there; scale compute + reroute)  ·  RPO: seconds (continuous geo-replication)\nlow-moderate cost — one small always-on replica. Azure: SQL active geo-replication + Front Door.",
      "color": "gray",
      "size": 12
    }
  },
  "meta": {
    "createdAt": "2026-07-20T09:00:00.000Z",
    "modifiedAt": "2026-07-20T09:00:00.000Z"
  }
}