How much Java Heap Space for Client Nodes

Elastic Stack Elasticsearch
#1

It is recommended to use less than half of your OS memory to Lucene, see https://www.elastic.co/guide/en/elasticsearch/guide/current/heap-sizing.html

I wonder whether this is also true for the Client nodes. Do ES Client nodes also need half of the available memory for Lucene, since it seems that the Client nodes are mostly doing the merging from the Data nodes. What is recommended?

Tribe node limitations / memory requirements?
Elasticsearch 6.5.4 - Kibana Coord Nodes OutOfMemory Errors And General Cluster Improvement Questions
#2

For client and tribe nodes (as well as master-only nodes), allocating half of OS memory for off-heap operations is not necessary. Merging results from the data nodes does not use off-heap memory.

2 Likes
#3

I'd suggest giving 75% of RAM to client nodes, up to the standard ~32GB limit.

#4