Sizing Elasticsearch

[yeziblo]

Hi everyone,

I want to plan the ES cluster reasonably:

1. I have 15 nodes and each nodes have 125G RAM and 31 CPU;
2. The total size of data is 30T(include replica);
3. The total count of shards is 7100(include replica);
4. Es version is 6.8.0;
5. index and search are all frequently;

How do I size my cluster? (how many master node do i need? Whether several coordinate nodes are required)

Best Regards!

[Christian_Dahlqvist]

@yeziblo

How do I size my cluster

It sounds like you have already sized your cluster and have it up and running. How is it performing?

@yeziblo

how many master node do i need?

You generally should have at least 3 master-eligible nodes, but 3 is often the optimal number. If your cluster is deployed across a larger number of availability zones/racks you may increase this.

@yeziblo

Whether several coordinate nodes are required

This depends a lot on the use case, as coordinating-only nodes are often not required. If you have a lot of querying you can add this type of node to see if it improves performance. Set the number so they are under reasonable load.

[yeziblo]

@Christian_Dahlqvist Yes, the cluster had been running for some time before I took over，and because the cluster's configuration is default value, query efficiency is not ideal.

I want to optimize the cluster by resizeing the cluster.

But I found that although I knew some theory, I still didn't know how to start in practice…

for example:
Does 125G ram is too big to a node(es node's jvm can not cross 32G)? is it better to deploy multiple es instances on one node?

[Christian_Dahlqvist]

Your setup looks reasonable. Have you identified what is limiting performance? Is it CPU? Disk I/O and utilisation? Heap pressure and GC?

What does the workload look like?

[yeziblo]

Hi, @Christian_Dahlqvist

the workload now looks good:

but sometimes the query efficiency is not good.

Do I need to set up extra ES instances on each node? I think 125GB is too much big.