# Set Up a Cluster
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**Prerequisites:** Prior to setting up a database, please make sure you are working within a provisioned [VDC](https://app.gitbook.com/s/-Mj91LQrRzfHvr2Jl2Rv/general-information/glossary-of-terms#vdc) that contains at least one [virtual machine](https://docs.ionos.com/support/general-information/glossary-of-terms#virtual-machine-vm) from which to access the database. The VM you create is counted against the quota allocated in your contract.
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**Note:** Database Manager is available only for contract administrators, owners, and users with **Access and manage DBaaS** privilege. You can set the privilege via the DCD group privileges.
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### Creating a Cluster
1\. To create a Postgres cluster, go to **Menu** > **Databases**.
2\. In the **Databases** tab, click **+ Add** in the **Postgres Clusters** section to create a new Postgres Cluster.
3\. Provide an appropriate **Display Name**.
4\. To create a Postgres Cluster from the available backups directly, you can go to the **Create from Backup** section and follow these steps:
* Select a **Backup** from the list of cluster backups in the dropdown.
* Select the **Recovery Target Time** field. A modal will open up.
* Select the **recovery date** from the calendar.
* Then, select the **recovery time** using the clock.
5\. Choose a **Location** where your data for the database cluster will be stored. You can select an available datacenter within the cluster's data directory to create your cluster.
6\. Select a **Backup Location** that is explicitly your backup location (region). You can have off-site backups by using a region that is not included in your database region.
7\. In the **Cluster to Datacenter Connection** section, provide the following information:
* **Data Center:** Select a datacenter from the available list.
* **LAN:** Select a LAN for your datacenter.
* **Private IP/Subnet:** Enter the private IP or subnet using the available [Private IPs](https://www.ionos.com/help/server-cloud-infrastructure/private-network/private-ip-address-ranges/).
* Once done, click the **Add Connection** option to establish your cluster to datacenter connection.
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**Note:** To know your **private IP address/Subnet**, you need to:
* Create a single server connected to an empty private LAN and check the IP assigned to that NIC in that LAN. The **DHCP** in that LAN always uses a **/24 subnet**, so you must reuse the **first 3 IP blocks** to reach your database.
* To prevent a collision with the DHCP IP range, it is recommended to use IP addresses ending between **x.x.x.3/24** and **x.x.x.10/24** (which are never assigned by DHCP).
* If you have disabled DHCP on your private LAN, you must discover the IP address on your own.
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8\. Select the appropriate **Postgres Version**. IONOS Database Manager supports versions 11, 12, 13, 14, and 15.
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**Deprecation Notice:** Support for version 11 will soon be removed and should not be used for new clusters.
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9\. Enter the number of **Postgres Instances** in the cluster. One Postgres instance always manages the data of exactly one database cluster.
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**Note:** Here, you will have a **primary** node and one or more standby nodes that run a copy of the active database, so you have **n-1 standby** instances in the cluster.
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10\. Select the mode of replication in the **Synchronization Mode** field; asynchronous mode is selected by default. The following are the available replication modes:
* **Asynchronous mode:** In asynchronous mode, the primary PostgreSQL instance does not wait for a replica to indicate that it wrote the data. The cluster can lose some committed transactions to ensure availability.
* **Synchronous mode:** Synchronous replication allows the primary node to be run standalone. The primary PostgreSQL instance will wait for any or all replicas. So, no transactions are lost during failover.
* **Strictly Synchronous:** It is similar to the synchronous mode but requires two operating nodes.
11\. Provide the initial values for the following:
* **CPU Cores**: Select the number of CPU cores using the slider or choose from the available shortcut values.
* **RAM Size**: Select the RAM size using the slider or choose from the available shortcut values.
* **Storage Type**: [SSD Premium](https://app.gitbook.com/s/-Mj91LQrRzfHvr2Jl2Rv/general-information/glossary-of-terms#ssd) is set by default.
* **Storage Size**: Enter the size value in Gigabytes.
The **Estimated price** will be displayed based on the input. The estimated cost is exclusive, where certain variables like traffic and backup are not considered.
12\. Provide the **Database User Credentials**, such as a suitable username and an associated password.
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**Note:** The credentials will be overwritten if the user already exists in the backup.
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13\. In the **Maintenance Window** section, you can set a **Maintenance time** using the pre-defined format (hh:mm:ss) or the clock. Select a **Maintenance day** from the dropdown list. The maintenance occurs in a **4-hour-long window**. So, adjust the time accordingly.
14\. Click **Save** to create the Postgres Cluster.
Your Postgres Cluster is now created.