L4 ElastiCache Overview

1、AWS ElastiCache Overview

1. The same way RDS is to get managed Relational Databases...
2. ElastiCache is to get managed Redis or Memcached
3. Caches are in-memory databases with really high performance, low latency
4. Helps reduce load off of databases for read intensive workloads
5. Helps make your application stateless
6. Write Scaling using sharding Read Scaling using Read Replicas
7. Multi AZ with Failover Capability
8. AWS takes care of OS maintenance / patching, optimizations, setup, configuration, monitoring, failure recovery and backups

2、Redis Overview

• Redis is an in-memory key-value store
• Super low latency (sub ms)
• Cache survive reboots by default (it's called persistence)

• Great to host

  • User sessions
  • Leaderboard (for gaming)
  • Distributed states
  • Relieve pressure on databases (such as RDS)
  • Pub / Sub capability for messaging

• Multi AZ with Automatic Failover for disaster recovery if you don't want to lose your cache data

• Support for Read Replicas

3、Memcached Overview

• Memcached is an in-memory object store
• Cache doesn't survive reboots

• Use cases:

  • Quick retrieval of objects from memory
  • Cache often accessed objects

• Overall, Redis has largely grown in popularity and has better feature sets than Memcached.

• I would personally only use Redis for caching needs.