ElastiCache

Introduction

• In-memory data stores on AWS.

• Types:

  • Redis

  • Memcached

Feature

• AWS takes care of the OS maintenance / patching, optimizations, setup, configuration, monitoring, failure recovery and backups.

• Using ElastiCache involves heavy application code change.

• Scenario steps:

  • Lifting load from DB

  • If data found from cache, return data.

  • If data not found from cache, read from DB. Then write it to cache.

  • Must have an invalidation strategy to avoid consistency problem.

• ElastiCache - Memcached vs Redis

  • Memcached

    • Multi-node for partitioning of data (sharding)

    • Non-persistent

    • No backup and restore

    • Multi-threaded architecture

  • Redis

    • Can scale up / down dynamically through CLI / console

    • Multi AZ with auto-failover

    • With Read replicas to scale with high availability

    • Persistent durability:

      • Enable Append-only file (AOF) for manual backups: logs every write operation received by the server, that will be played again at server startup, reconstructing the original dataset.

ElastiCache - Memcached, Redis

Handling Extreme Rates

Extreme rates in AWS architecture

• The more components are used in the right, more cost would occur. Try to utilize components in the left.