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amazon-elasticache

ElastiCache not utilizing read only replica


I have a simple Redis ElastiCache cluster (cluster mode disabled) with a master node and a read only replica.

When throwing traffic at the server, i.e. from redis-benchmark, it seems all GET traffic goes only to the master node, while the RO replica gets zero GET traffic (cache hit/miss and GetTypeCommands are all 0).

Anyone has insights on why this is happening? I expected the traffic would be distributed between the two nodes.


Solution

  • older question but I am answering since I am just learning this myself...

    I thought that the purpose was to balance the load between master and slave, but that is not the case. The slave exists so that it can be promoted to master if master fails for any reason.

    further reading: https://redis.io/topics/replication