• ElastiCache is a web service
  • Used to set up, manage, and scale distributed in-memory cache environments in AWS.
  • Provides a high performance, resizable, and cost-effective in-memory cache
  • Removes complexity associated with deploying and managing a distributed cache environment.
  • Works with the Redis and Memcached engines
  • By default, the AWS SDKs, AWS CLI, ElastiCache API, and ElastiCache console reference the US-West (Oregon) region.
  • is a web service
  • makes it easy to
    • deploy
    • operate
    • scale an in-memory data store or cache in the cloud.
  • Can be used for DB caching in conjunction with services like RDS
  • Web service that makes it easy to deploy, operate, and scale in memory cache in the cloud
  • 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
  • Improves application performance by storing critical pieces of data in memory for low-latency access
  • Cached information may include the results of I/O intensive database queries or the results of computationally intensive calculations
  • Supports 2 open-source in-memory caching engines:
    • Memcached:
      • Widely adopted memory object caching system
      • Elasticache is protocol complaint with memcached, so popular tools that you use today with existing memcached environments will work seamlessly with the service
      • No Multi AZ support
    • Redis:
      • Popular open-source in-memory key-value store that supports data structures such as sorted sets and lists
      • Elasticache supports Master/Slave replication and Multi-AZ which can be used to achieve cross AZ redundancy
      • Good choice if db is read heavy and not prone to frequent changing
All Region Resource or OperationDefaultLimitDescription
Nodes per region:50The maximum number of nodes across all clusters in a region.
Nodes per cluster (Memcached):20The maximum number of nodes in an individual Memcached cluster.
Nodes per cluster (Redis):1The maximum number of nodes in an individual Redis cluster.
Clusters per replication group (Redis):6The maximum number of clusters in a Redis replication group. One is the read/write primary. All others are read only replicas.
Parameter groups per region:20The maximum number of parameters groups you can create in a region.
Security groups per region:50The maximum number of security groups you can create in a region.
Subnet groups per region:50The maximum number of subnet groups you can create in a region.
Subnets per subnet group:20The maximum number of subnets you can define for a subnet group.

ElastiCache Node

  • Node is the smallest building block in Elasticache
  • Node can exist in isolation from
  • Node can be in some relationship to other nodes.
  • It is a fixed-size chunk of secure, network-attached RAM.
  • Each node runs an instance of the engine and version that was chosen during cluster creation.
  • Scale the nodes in a cluster up or down to a different instance type.

ElastiCache operations for clusters:

  • Creating a cluster
  • Modifying a cluster
  • Taking snapshots of a cluster (all versions of Redis)
  • Deleting a cluster
  • Viewing the elements in a cluster
  • Adding or removing cost allocation tags to and from a cluster