The amount of data your application needs to process is seldom static. It increases and decreases as your business grows or experiences normal fluctuations in demand. If you self-manage your cache, you need to provision sufficient hardware for your demand peaks, which can be expensive. By using Amazon ElastiCache you can scale to meet current demand, paying only for what you use. ElastiCache enables you to scale your cache to match demand.
Amazon ElastiCache does not support modifying a Redis (cluster mode enabled) replication group. Therefore, the only way to scale your Redis (cluster mode enabled) replication group is to create a new replication group which has the node type, number of node groups, and number of replicas per node group you want to scale to, and then delete the existing replication group. If you are not changing the number of node groups, you can seed the new replication group with data from the existing replication group. For more information, see ElastiCache Backup and Restore (Redis).