# How much Java Heap Space for Client Nodes **URL:** \ **Category:** Elasticsearch\ **Created:** [July 29, 2016, 10:32am UTC](https://discuss.elastic.co/t/how-much-java-heap-space-for-client-nodes/56719 "2016-07-29T10:32:59Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![drjz](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/drjz/32/972_2.png) [@drjz](https://discuss.elastic.co/u/drjz)\ **Post date:** [July 29, 2016, 10:32am UTC](https://discuss.elastic.co/t/how-much-java-heap-space-for-client-nodes/56719/1 "2016-07-29T10:32:59Z")
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](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? ---
**Author:** ![ywelsch](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ywelsch/32/7751_2.png) [@ywelsch](https://discuss.elastic.co/u/ywelsch)\ **Post date:** [July 29, 2016, 1:40pm UTC](https://discuss.elastic.co/t/how-much-java-heap-space-for-client-nodes/56719/2 "2016-07-29T13:40:14Z")
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. ---
**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\ **Post date:** [July 31, 2016, 12:06am UTC](https://discuss.elastic.co/t/how-much-java-heap-space-for-client-nodes/56719/3 "2016-07-31T00:06:40Z")
I'd suggest giving 75% of RAM to client nodes, up to the standard ~32GB limit. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 5, 2017, 10:31pm UTC](https://discuss.elastic.co/t/how-much-java-heap-space-for-client-nodes/56719/4 "2017-07-05T22:31:31Z")