Replication Across AWS Regions Using Global Datastores - Amazon ElastiCache for Redis

Replication Across AWS Regions Using Global Datastores

By using the Global Datastore for Redis feature, you can work with fully managed, fast, reliable, and secure replication across AWS Regions. Using this feature, you can create cross-Region read replica clusters for ElastiCache for Redis to enable low-latency reads and disaster recovery across AWS Regions.

In the following sections, you can find a description of how to work with global datastores.

Overview

Each global datastore is a collection of one or more clusters that replicate to one another.

A global datastore consists of the following:

  • Primary (active) cluster – A primary cluster accepts writes that are replicated to all clusters within the global datastore. A primary cluster also accepts read requests.

  • Secondary (passive) cluster – A secondary cluster only accepts read requests and replicates data updates from a primary cluster. A secondary cluster needs to be in a different AWS Region than the primary cluster.

When you create a global datastore in ElastiCache, ElastiCache for Redis automatically replicates your data from the primary cluster to the secondary cluster. You choose the AWS Region where the Redis data should be replicated and then create a secondary cluster in that AWS Region. ElastiCache then sets up and manages automatic, asynchronous replication of data between the two clusters.

Using a global datastore for Redis provides the following advantages:

  • Geolocal performance – By setting up remote replica clusters in additional AWS Regions and synchronizing your data between them, you can reduce latency of data access in that AWS Region. A global datastore can help increase the responsiveness of your application by serving low-latency, geolocal reads across AWS Regions.

  • Disaster recovery – If your primary cluster in a global datastore experiences degradation, you can promote a secondary cluster as your new primary cluster. You can do so by connecting to any AWS Region that contains a secondary cluster.

The following diagram shows how global datastores can work.


            global datastore