# Scale a PostgreSQL Cluster Horizontally

DBaaS supports increasing and decreasing the amount of your database replicas. To do so, issue a `PATCH` request containing the new replica count (between `1` and `5`).

## Endpoint

Use the following endpoint to scale your PostgreSQL cluster horizontally :`https://api.ionos.com/databases/postgresql/clusters/{clusterId}`

{% hint style="info" %}
**Note:** The sample UUID is `498ae72f-411f-11eb-9d07-046c59cc737e`.
{% endhint %}

## Request

```bash
curl --include \
    --request PATCH \
    --user "clientname@ionos.com:Mb2.r5oHf-0t" \
    --header "Content-Type: application/json" \
    --data-binary '{
      "metadata": {},
      "properties": {
        "instances": 1
      }
    }' \
```

## Response

```json
{
  "type": "cluster",
  "id": "498ae72f-411f-11eb-9d07-046c59cc737e",
  "metadata": {
    "state": "AVAILABLE",
    "createdDate": "2020-12-10T12:37:50.000Z",
    "createdBy": "clientname@ionos.com",
    "createdByUserId": "012342f-411f-1eeb-9d07-046c59cc737e",
    "lastModifiedDate": "2020-12-18T21:37:50.000Z",
    "lastModifiedBy": "clientname@ionos.com",
    "lastModifiedByUserId": "012342f-411f-1eeb-9d07-046c59cc737e"
  },
    "properties": {
        "displayName": "an even better name",
        "location": "de/txl",
        "dnsName": "pg-pgov71sjg1c875ji.postgresql.de-txl.ionos.com",
        "connections": [
            {
                "datacenterId": "db7e8811-cfae-4b40-82ee-2f4cff81e105",
                "lanId": "2",
                "cidr": "10.7.222.3/23"
            }
        ],
        "cores": 4,
        "postgresVersion": "15",
        "ram": 4096,
        "instances": 1,
        "storageSize": 102400,
        "storageType": "HDD",
        "maintenanceWindow": {
            "dayOfTheWeek": "Wednesday",
            "time": "12:08:00"
        },
        "synchronizationMode": "ASYNCHRONOUS",
        "connectionPooler": {
            "enabled": false,
            "poolMode": "transaction"
        }
    }
  }
```

{% hint style="danger" %}
**Caution:** Scaling down can result in failovers and interrupt open connections.
{% endhint %}


---

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