What is a classic and recommanded ElasticSearch architecture?

Elastic Stack Elasticsearch
1

Our former cluster ES was made of 40 data nodes.

  • 4 of them were coordinators as well
  • 3 of them were electable as a master (for one node, it gathers data, coordinator and master-electable role)

We aim to create a new cluster (with 40 nodes as well) and I was wondering if it is recommanded to dedicate to a node, a specific role (ie. a coordinating node does not contain data node, etc.) ?

For example, does a node being both data and coordinator is an anti-pattern ?
Indeed, on a same node, I presume that a coordinator that falls can impact the data node part ?

Thanks.

2

Dedicated master nodes should neither store or serve traffic. Beyond that you can have each node doing multiple roles.

It depends on your use case and requirements really.