# Set Up a PostgreSQL Cluster
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**Prerequisites:** Prior to setting up a database, please make sure you are working within a provisioned [VDC](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#vdc) that contains at least one [virtual machine](https://docs.ionos.com/cloud/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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## Create a Cluster
To create a Postgres cluster, follow these steps:
1\. In the **DCD**, go to **Menu** > **Databases** > **PostgreSQL**.
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**Info:** The **Resource allocation** section displays the resources allotted to your contract and the number of used and unused resources if you have already created PostgreSQL clusters.
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2\. In the **PostgreSQL cluster overview** window, click **Create cluster** to create a new Postgres cluster.
3\. Specify the following:
* Provide an appropriate **Cluster Name**.
* Select 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.
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 cluster** from the drop-down list of cluster backups.
* Click the Calendar icon in the **Recover target time** field to select a date and time:
* Select the **recovery date** from the calendar.
* Select the **recovery time** using the clock.
5\. To configure your Cluster, enter the following details in the **Cluster configuration** section:
a. Select the appropriate **PostgreSQL Version**. IONOS Cloud Database Manager supports versions 14, 15, and 16.
b. Enter the number of **Instances** in the cluster. One PostgreSQL instance always manages the data of exactly one database cluster. You can create a maximum of five instances within a 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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c. Select the mode of replication in the **Synchronization mode** field; **Asynchronous** mode is selected by default. The following are the available replication modes:
* **Asynchronous:** 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:** 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.
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**Note:**
* You must choose either **Asynchronous** or **Strictly Synchronous**, as **Synchronous** replication mode is deprecated and will be fully removed in upcoming releases.
* You can update the existing clusters on **Synchronous** mode to either **Asynchronous** or **Strictly Synchronous** using the [Update PostgreSQL Replication Mode](https://docs.ionos.com/sections-test/guides/databases/postgresql/api/v1-api/modify-cluster-attributes/update-postgresql-replication-mode) API.
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* **Strictly Synchronous:** It is similar to the synchronous mode but requires two operating nodes.
d. 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.
6\. Specify the following in the **Instance configuration** section:
* **Number of CPUs (per instance)**: Select the number of CPU cores using the slider or choose from the available shortcut values.
* **RAM Size (per instance)**: Select the RAM size using the slider or choose from the available shortcut values.
* **Storage Type**: Select a storage type for your instance. [HDD](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#hdd) is set by default.
* **Storage Size**: Enter the storage size value in Gigabytes.
7\. In the **Network configuration** section, provide the following information to connect your cluster with the datacenter:
* **Datacenter:** Select a datacenter from the available list.
* **Datacenter LAN:** Select a LAN for your datacenter.
* **Private IP:** Select a private IP address from the drop-down list. For more information, see [Private IP Address Ranges](https://www.ionos.com/help/server-cloud-infrastructure/private-network/private-ip-address-ranges/).
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**Note:** To know your **private IP address/Subnet**, you must:
* 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 octets** 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\. In the **Maintenance period (optional)** section, you can set a maintenance day and time using the pre-defined format (hh:mm:ss) or the clock.
* Select a **Day** from the drop-down list.
* Enter a **Start Time (UTC)** using the pre-defined format (hh:mm:ss) to schedule the maintenance task. You can also click the  icon to set a time.
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**Note:** We recommend choosing the day and time appropriately because the maintenance occurs in a **4-hour-long window**.
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9\. Provide the following details in the **User Creation** section:
* **Username:** Enter a username to provide access to the Postgres Cluster for the respective user.
* **Password:** Enter a password for the respective user.
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**Note:** The credentials will be overwritten if the user already exists in the backup.
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**Result:** The **Estimated costs** will be displayed based on the input. It is exclusive and certain variables like traffic and backup are not considered.
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10\. Click **Save** to create the Postgres Cluster.
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**Result:** Your Postgres Cluster is now created.
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