Reliability

Momento Cache operates your Valkey Capacity Pool as a managed, replicated cluster, delivering high availability with zero maintenance. This page describes how the service achieves reliable performance and what you can configure.

Replication

Each shard in a Capacity Pool can have zero, one, or more replica nodes in addition to the active primary node. Set replicas_per_shard to at least one in production so that the data in a shard will survive the loss of a node.

Multi-AZ placement

Use multiple availability zones for production deployments. You configure which zones a Capacity Pool can use, while Momento automatically distributes Valkey nodes across those zones. Choose two or more availability zones in production so that the pool survives the loss of a single zone.

Managed operation

The Momento Cache control plane manages the underlying cluster based on your specified configuration. It automatically provisions and replaces nodes, including promotion of a replica when a primary is lost (failover). Momento automatically applies CVE patches and version upgrades so that you never have to worry about being out of date.

Automatic Rolling Updates

Changes to a pool's configuration, including instance-type upgrades, are applied as a rolling update. The service replaces nodes one at a time, bringing up the new node and waiting for it to become healthy before removing the old node, so that the pool continues serving without disruptions.