CODEWITHSUNDEEP
redisgoogle-kubernetes-engine
Sam Leurs
Sam Leurs

Reputation: 2000

redis cluster total size

I have a quick question about redis cluster.

I'm setting up a redis cluster on google cloud kubernetes engine. I'm using the n1-highmem-2 machine type with 13GB RAM, but I'm slightly confused how to calculate the total available size of the cluster.

I have 3 nodes with each 13GB ram. I'm running 6 pods (2 on each node), 1 master and 1 slave per node. This all works. I've assigned 6GB of RAM to each pod in my pod definition yaml file.

Is it correct to say that my total cluster size would be 18GB (3 masters * 6GB), or can I count the slaves size with the total size of the redis cluster?

Upvotes: 1

Views: 461

Answers (1)

Will R.O.F.
Will R.O.F.

Reputation: 4108

Redis Cluster master-slave model

In order to remain available when a subset of master nodes are failing or are not able to communicate with the majority of nodes, Redis Cluster uses a master-slave model where every hash slot has from 1 (the master itself) to N replicas (N-1 additional slaves nodes).

So, slaves are replicas(read only) of masters(read-write) for availability, hence your total workable size is the size of your master pods.

Keep in mind though, that leaving masters and slaves on the same Kubernetes node only protects from pod failure, not node failure and you should consider redistributing them.

You didn't mention how are you installing Redis, But I'd like to mention Bitnami Redis Helm Chart as it's built for use even on production and deploys 1 master and 3 slaves providing good fail tolerance and have tons of configurations easily personalized using the values.yaml file.

Upvotes: 1

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