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How to create Read Replicas

Reviewed on 13 June 2023Published on 01 September 2022

A Read Replica is a live copy of a Database Instance that behaves like an Instance, but that only allows read-only connections. The replica mirrors the data of the primary Database node and any changes made are replicated to the replica asynchronously.

Read replicas allow you to scale your Database Instance for read-heavy database workloads. They can also be used for business intelligence workloads.

Security & Identity (IAM):

You may need certain IAM permissions to carry out some actions described on this page. This means:

  • you are the Owner of the Scaleway Organization in which the actions will be carried out, or
  • you are an IAM user of the Organization, with a policy granting you the necessary permission sets
Requirements:
  1. Click PostgreSQL and MySQL under Managed Databases on the side menu. A list of your Database Instances displays.

  2. Click the database name or «See more Icon» > More info to access the Database Instance information page.

  3. Scroll down to the Read Replica section.

  4. Click Create Read Replica. A pop-up displays.

  5. Select the Availability Zone (AZ) configuration. Two configurations are available:

    • Same AZ: Your Read Replica is hosted in the same AZ as your main Database Instance. We recommend this option for low-latency workflows.
    • Multi-AZ: Your Read Replica is hosted in a different AZ, ensuring the resilience of your Replica. We recommend this option for ensuring the availability of your infrastructure, and improving your disaster recovery plan.
  6. Select the network type. Two types are available:

    • Public network - Resources in a public network are publicly visible by default. The default Access Control List (ACL) settings allow anybody to connect to resources in your network. You can restrict access by configuring ACLs in the Allowed IPs section.
    • Private Networks - Private Networks allow you to create virtual Private Networks for your Databases, enabling them to communicate in an isolated network without the need for a public IP address. If you select this option, you must select an existing Private Network to attach to your Read Replica.
    Note:

    Your private IP addresses are automatically allocated. They are managed via an IP Address Manager (IPAM). You can retrieve them on the Private Network tab of your Database Instance. To allocate IPs manually, you can use the Scaleway API and CLI, or Terraform.

    Important:

    If you select Public network, you can attach a Private Network to your Read Replica after its creation. If you chose to attach your Read Replica to a Private Network, you will not be able to add a Public Network to the same Read Replica later via the Scaleway console. You can, however, use the Managed Databases API to do so via a command line or Terraform.

  7. Click Create Read Replica. A list of your Read Replicas displays.

    Important:

    Read Replicas have the same node types as the main node. For example, if your main node is of the DB-GP-S type, so is your Read Replica. The Replica also inherits the main node’s configuration. The data of your main node is fully replicated in the Read Replica.

    Note:

    The time it takes to create the Read Replica depends on the volume of data being replicated.

See Also