Deployment topologies

In-memory

Redis

Redis active-active storage

The RedisLabs version of Redis supports active-active replication. Limitador is compatible with that deployment mode, but there are a few things to take into account regarding limit accuracy.

Considerations

With an active-active deployment, the data needs to be replicated between instances. An update in an instance takes a short time to be reflected in the other. That time lag depends mainly on the network speed between the Redis instances, and it affects the accuracy of the rate-limiting performed by Limitador because it can go over limits while the updates of the counters are being replicated.

The impact of that greatly depends on the use case. With limits of a few seconds, and a low number of hits, we could easily go over limits. On the other hand, if we have defined limits with a high number of hits and a long period, the effect will be basically negligible. For example, if we define a limit of one hour, and we know that the data takes around one second to be replicated, the accuracy loss is going to be negligible.

Set up

In order to try active-active replication, you can follow this tutorial from RedisLabs.

Disk

Disk storage using RocksDB. Counters are held on disk (persistent).