Redis Administration

This page contains topics related to the administration of Redis instances. Every topic is self contained in form of a FAQ. New topics will be created in the future.

Redis setup hints

Running Redis on EC2

Upgrading or restarting a Redis instance without downtime

Redis is designed to be a very long running process in your server. For instance many configuration options can be modified without any kind of restart using the CONFIG SET command.

Starting from Redis 2.2 it is even possible to switch from AOF to RDB snapshots persistence or the other way around without restarting Redis. Check the output of the CONFIG GET * command for more information.

However from time to time a restart is mandatory, for instance in order to upgrade the Redis process to a newer version, or when you need to modify some configuration parameter that is currently not supported by the CONFIG command.

The following steps provide a very commonly used way in order to avoid any downtime.

If you are using Redis Sentinel or Redis Cluster, the simplest way in order to upgrade to newer versions, is to upgrade a slave after the other, then perform a manual fail-over in order to promote one of the upgraded slaves as master, and finally promote the last slave.

Note however that Redis Cluster 4.0 is not compatible with Redis Cluster 3.2 at cluster bus protocol level, so a mass restart is needed in this case.