Elasticache

Description

It's a web service that makes it easy to deploy operate and scale in-memory caching in the cloud.
Speed up performance of existing databases (frequent identical queries).
The service improves the performance of Web applications by allowing you to retrieve information from fast managed in memory caches instead of relying on slower disk space databases.
Elasticache can store (cache) frequent queries that does not change alot.
So, your web server can query Elasticache first for commonly requested queries and only retrieve data from database if query is not cached in Elasticache.
This takes an enormous strain of your database.

Caching EnginesX

- Support 2 open-source in-memory caching engines:
  1 Memcached
  2 Redis
                                    

Requirement	Memcached	Redis
Simple Cache to offload DB	Yes	Yes
Ability to scale horizontally	Yes	Yes
Multi-threaded performance	Yes	No
Advanced data types	No	Yes
Ranking/Sorting data sets	No	Yes
Publishing/Subscribing capabilities	No	Yes
Persistence	No	Yes
Multi-AZ	No	Yes
Backup & Restore Capabilities	No	Yes

Redis

Using Redis AUTH command can improve data security by requiring the user to enter a password before they are granted permission to execute Redis commands on a password-protected Redis server.
To require that users enter a password on a password-protected Redis server, include the parameter --auth-token with the correct password when you create your replication group or cluster and on all subsequent commands to the replication group or cluster.