Ensuring data persistence

Data persistence ensures that the data from your applications is saved, in memory or on a disk, even when there are no ongoing sessions where the data is treated. The method used to preserve data between sessions and avoid data loss varies depending on the compute resource you use to treat your data. It also depends on the way your data is stored.

When data is stored in memory, and no data persistence strategy is put in place, the data will be gone any time the compute process is stopped.

To avoid this, Redis™^* natively supports persistence by performing snapshots.

This feature is supported and managed by Scaleway with Managed Databases for Redis™.

Furthermore, you can leverage the cluster mode to ensure the durability of your data.

Snapshots

Snapshots are available by default with a fixed configuration.

When you create a new Redis™ Database Instance, a Redis™ snapshot is also automatically created within specified intervals. These are:

• 900 seconds if one key has been updated
• 300 seconds if 10 keys have been updated
• 60 seconds if 10 000 keys have been updated

Cluster mode

If you want to benefit from fault-tolerant architecture in some use cases, we recommend you deploy Redis™ in cluster mode, where each primary node is deployed with a replica node.

A Redis cluster contains a minimum of three nodes and up to six nodes. Each node contains a source and a replica. The cluster nodes use hash partitioning to split the keyspace into key slots. Each replica copies the data of a specific source and can be reassigned to replicate another source or be elected as a source node if needed. This is recommended for scaling as the operation is spread across multiple nodes instead of having a single entry point.

High Availability

High Availability is a Database Instance configuration that allows you to create a standby node, with an up-to-date replica of the database. If the main node fails for any reason, the standby can take over requests, reducing downtime.

The HA standby node is linked to the main node, using asynchronous replication. Asynchronous replication allows to keep good performances.