About scaling instance capacity

This page describes how your Memorystore for Redis Cluster instance behaves during scaling. To scale capacity up or down, you change the number of shards in your cluster. For information about the different types and sizes of shards, see Cluster and node specification.

To learn how to scale a Redis instance, see Scale instances.

Impact of scaling

Your instance availability is not impacted during scaling.

During a scaling operation your instance's keyspace is rebalanced. This can cause increased latency during the scaling operation.

Failure scenarios

If you encounter an error during the scaling operation, it is likely due to one of the following:

  • Scaling can fail if you scale to an smaller instance size that doesn't have the capacity to hold all of the keys currently stored in the instance.
  • Scaling can fail if you scale the instance during a period of particularly high write pressure, for example, during load testing.