High Availability
Redis Enterprise is a self-managed, real-time data platform that unlocks the full potential of Redis at scale, ensuring five-nines (5-9s) high availability.
Redis Enterprise’s high availability is built around replication, but automatic failover, backup, and recovery also impact the ability to meet the application’s high availability service level agreements.
Replication is the process of storing identical copies of your data on multiple Redis Enterprise servers. Redis Enterprise replication keeps your data safe and allows your application to run uninterrupted, without downtime, keeping it highly available, even if something happens to one or more of your servers.
Cost-effective replication
Like most NoSQL database deployments, open source Redis uses three replicas to ensure high availability. From a high-level perspective, the first replica is usually used to store your dataset, the second for failover purposes, and the third serves as a tiebreaker in case of a network split event. Because DRAM is expensive, maintaining three replicas can be extremely expensive. Redis Enterprise allows you to have a complete high availability (HA) system with only two replicas. Your tiebreaker is determined at the node level by using an uneven number of nodes in a cluster. The example below compares the infrastructure cost of running a 90GB high availability architecture with an open source Redis dataset on Amazon Web Services with three replicas as opposed to with a Redis Enterprise cluster that uses two replicas and a quorum node: