Cache

• A good overview can be found here.

• Used in managing state of stateless application, reduce load off of databases for read intensive workloads etc.

Caching Strategies

• Some common strategy based on operation done on the system can be found here.

• Most popular strategies are,

  • Lazy Loading/Cache Aside/Lazy Population

  • Write Through

Elasti Cache

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Elasti Cache Icon

About

• Caches are in-memory databases with high performance and low latency.

• Being a managed service following tasks are managed by AWS,

  • OS maintenance/patching

  • Optimizations

  • Setup

  • Configuration

  • Monitoring

  • Failure recovery and backups

• Offers managed Redis or Memcached variants.

• For redis in cluster mode, there can be upto 5 read replicas.

Cache evictions

• Cache eviction can occur in 3 ways

  • Delete the item explicitly in the cache

  • Item is evicted because the memory is full and is not recently used.

  • You set an item's time-to-live, where in TTL can vary from a few second to hours or days.

• If too many evictions happen due to memory, you should scale up or out.

Security

• Encryption at rest and transit is available to make sure data is secure.

References

• Types of caching

• Best Caching practices