To scale Redis reads, you can use several techniques. They mainly involve using Redis' replication feature or partitioning your data across multiple instances. It's also useful to employ load balancing to distribute read operations evenly.
Replication in Redis allows you to create a copy of your data on secondary Redis servers (slaves). By default, clients can send read queries to these replicas to distribute the load and thereby increase read scalability.
Remember that the write operations need to be performed on the master server as they are not automatically propagated from the slaves to the master.
Partitioning in Redis involves splitting your data across multiple Redis instances. There are several types of partitioning available, like range partitioning, hash partitioning, list partitioning, etc. Each of them has its own pros and cons, so you'll need to choose based on your specific use-case.
Load balancing can be used together with replication to distribute the load evenly across multiple nodes. This can be done using software like HAProxy, or cloud service providers' load balancers if your infrastructure is based on the cloud.
Using Redis Cluster
As of Redis 3.0, there's native support for automatic partitioning across multiple nodes with Redis Cluster. It includes automatic data sharding and provides high availability through automatic failover.
Remember that while scaling reads can improve performance, it may also introduce additional complexity in terms of maintaining consistency across multiple nodes, especially when writing data. Always test thoroughly before implementing these solutions in production environments.