We are pleased to announce a public preview of the geo-replication functionality in the Azure Redis service. Geo-replication gives you the ability to link Redis caches across different Azure regions to form a primary-replica relationship. It provides an ingredient necessary for any disaster recovery design in your application. Geo-replication preview is available now for all premium Azure Redis caches. At present, we support having one primary cache and one replica in a geo-redundant configuration.
To setup geo-replication, you need two instances of Azure Redis premium cache belonging to one Azure subscription, one to be used as the primary and the other as the replica. You create the replica cache in exactly the same way that you have created the primary. The replica cache needs to be equal or bigger in size than the primary cache and, additionally, have a matching number of shards if the primary cache is clustered. While there is no requirement for the two caches to be located in different Azure regions, that is the most commonly expected case. If they reside in VNET(s), the caches must be able to reach each other. You can refer to this GitHub document for the current list requirements and restrictions for using geo-replication.