Database replication helps ensure high availability.

When replication is enabled, your dataset is duplicated to create a replica that is synchronized with the primary dataset.

Replication allows for automatic failover and greater fault tolerance. It can prevent data loss in the event of a hardware or zone failure.

Options and plan support

Redis Cloud supports three levels of replication:

  • No replication means that you will have a single copy of your database.

  • Single-zone replication means that your database will have a primary and a replica located in the same cloud zone. If anything happens to the primary, the replica takes over and becomes the new primary.

  • Multi-zone replication means that the primary and its replicas are stored in different zones. This means that your database can remain online even if an entire zone becomes unavailable.

Your replication options depend on your subscription plan:

  • Free plans do not support replication.
  • Fixed, Flexible and Annual paid plans let you choose between multi-zone or single-zone replication when creating a subscription. You can also turn off replication.

After database creation, you can still enable or turn off replication. However, zone settings are only configurable during database creation.

Performance impact

Replication can affect performance as traffic increases to synchronize all copies.

Memory limit

For both Fixed and Flexible plans, replication doubles the memory limit you need for your database.

For Fixed plans, The size of the plan you choose includes replication. Therefore, if you choose replication, the dataset size you can use is half of the stated plan size. For example, if you choose a 1GB plan, Redis allocates 512 GB for the memory limit, and the other 512 MB for Replication.

For Flexible and Annual plans, you also need to double the amount of memory needed if you choose replication.

Zone setting maintenance

Zone settings can only be defined when a subscription is created. You cannot change these settings once the subscription becomes active.

This means you can’t convert a multi-zone subscription to a single zone (or vice-versa).

To use different zone settings, create a new subscription with the preferred settings and then migrate data from the original subscription.

More info

To learn more about high availability and replication, see: