Amazon ElastiCache vs Amazon RDS: What are the differences?

Developers describe Amazon ElastiCache as "Deploy, operate, and scale an in-memory cache in the cloud". ElastiCache improves the performance of web applications by allowing you to retrieve information from fast, managed, in-memory caches, instead of relying entirely on slower disk-based databases. ElastiCache supports Memcached and Redis. On the other hand, Amazon RDS is detailed as "Set up, operate, and scale a relational database in the cloud". Amazon RDS gives you access to the capabilities of a familiar MySQL, Oracle or Microsoft SQL Server database engine. This means that the code, applications, and tools you already use today with your existing databases can be used with Amazon RDS. Amazon RDS automatically patches the database software and backs up your database, storing the backups for a user-defined retention period and enabling point-in-time recovery. You benefit from the flexibility of being able to scale the compute resources or storage capacity associated with your Database Instance (DB Instance) via a single API call.

Amazon ElastiCache can be classified as a tool in the "Managed Memcache" category, while Amazon RDS is grouped under "SQL Database as a Service".

Some of the features offered by Amazon ElastiCache are:

• Support for two engines: Memcached and Redis
• Ease of management via the AWS Management Console. With a few clicks you can configure and launch instances for the engine you wish to use.
• Compatibility with the specific engine protocol. This means most of the client libraries will work with the respective engines they were built for - no additional changes or tweaking required.

On the other hand, Amazon RDS provides the following key features:

• Pre-configured Parameters
• Monitoring and Metrics
• Automatic Software Patching

"Redis" is the primary reason why developers consider Amazon ElastiCache over the competitors, whereas "Reliable failovers" was stated as the key factor in picking Amazon RDS.

According to the StackShare community, Amazon RDS has a broader approval, being mentioned in 1408 company stacks & 509 developers stacks; compared to Amazon ElastiCache, which is listed in 342 company stacks and 79 developer stacks.