For each node in the cluster, you can configure both persistent storage and ephemeral storage paths.

  • Persistent storage is mandatory. It is used by the cluster to store information that needs to persist even if a shard or a node fails, including server logs, configurations, files. For example, if you configure persistence for a database, then the persistence information is stored in this location.

    The persistent volume must be a SAN (Storage Area Network) using an EXT4 or XFS file system and be connected as an external storage volume.

    When using AOF persistence, we recommend that you use flash-based storage for the persistent volume.

  • Ephemeral storage is optional. If configured, the cluster stores temporary information that does not need to persist in the ephemeral storage. This improves performance and helps to reduce the load on the persistent storage.

    Ephemeral storage must be a locally attached volume on each node.

Note -
Persistent and ephemeral storage discussed here is not related to Redis persistence or AWS ephemeral drives.

For disk size requirements, see: