Amazon ElastiCache for Redis | Enhanced Engine

Question 1

Can I use my own RDB snapshots stored in S3 to pre-seed a scale out ElastiCache for Redis Cluster environment?

Enhanced Engine

Amazon ElastiCache for Redis | Database

Answer 1

Yes. You can specify the S3 location of your RDB files during cluster creation through the Create Cluster Wizard in the console or through the CreateReplicationGroup API. ElastiCache will automatically parse the Redis key-space of the RDB snapshot and redistribute it among the shards of the new cluster.

Question 2

How is the engine within ElastiCache for Redis different from open-source Redis?

Enhanced Engine

Amazon ElastiCache for Redis | Database

Answer 2

The engine within ElastiCache for Redis is fully compatible with open source Redis but also comes with enhancements that improve robustness and stability. Some of the enhancements are:

More usable memory: You can now safely allocate more memory for your application without risking increased swap usage during syncs and snapshots.

Improved synchronization: More robust synchronization under heavy load and when recovering from network disconnections. Additionally, syncs are faster as both the primary and replicas no longer use the disk for this operation.

Smoother failovers: In the event of a failover, your shard now recovers faster as replicas no longer flush their data to do a full re-sync with the primary.

Question 3

How do I use the enhanced engine?

Enhanced Engine

Amazon ElastiCache for Redis | Database

Answer 3

To use the enhanced engine from the Amazon ElastiCache management console, just select an engine compatible with Redis engine version 2.8.22 or higher when creating a cluster. From that point on you will be using the enhanced engine. You can also use the enhanced engine through the ElastiCache API or AWS CLI by specifying the engine version when running the CreateCacheCluster API.

Question 4

Do I need to change my application code to use the enhanced engine on ElastiCache?

Enhanced Engine

Amazon ElastiCache for Redis | Database

Answer 4

No. The enhanced engine is fully compatible with open-source Redis, thus you can enjoy its improved robustness and stability without the need to make any changes to your application code.