# Global Cluster

Global cluster mode enables multi-region Milvus deployments with automatic failover. The SDK fetches cluster topology from the endpoint and routes requests to the primary cluster.

## Enabling Global Cluster Mode

Set `isGlobal: true` in the client configuration:

```javascript
import { MilvusClient } from '@zilliz/milvus2-sdk-node';

const client = new MilvusClient({
  address: 'your-global-endpoint:19530',
  isGlobal: true,
  token: 'your-token',
});
```

### Auto-Detection

When `isGlobal` is not explicitly set, the SDK auto-detects global cluster mode by checking if the address URI contains `global-cluster`. You can override this by explicitly setting `isGlobal: true` or `isGlobal: false`.

## How It Works

When global cluster mode is enabled:

1. **Connection:** The SDK connects to the provided endpoint and queries the cluster topology
2. **Routing:** Requests are routed to the primary cluster automatically
3. **Failover:** If the primary cluster becomes unavailable, the SDK can reconnect to a new primary

## Manual Primary Reconnection

Use `reconnectToPrimary()` to manually trigger a reconnection to the current primary cluster:

```javascript
const changed = await client.reconnectToPrimary();

if (changed) {
  console.log('Reconnected to new primary cluster');
} else {
  console.log('Primary unchanged, no reconnection needed');
}
```

This method:
- Queries the endpoint for the current primary cluster
- If the primary has changed, creates a new connection pool for the new primary
- Drains the old connection pool gracefully
- Returns `true` if a reconnection occurred, `false` if the primary is unchanged

## Configuration

| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| `isGlobal` | `boolean` | Auto-detected | Enable/disable global cluster mode |
| `address` | `string` | Required | Global cluster endpoint address |
| `token` | `string` | - | Authentication token |

## Next Steps

- Learn about [Client Configuration](/core-concepts/client-configuration) for all connection options
- Explore [Advanced Features](/advanced/advanced-features) for connection pooling and retries

## Commit

```bash
git add docs/content/advanced/global-cluster.mdx
git commit --signoff -m "docs: add global cluster documentation page"
```