# Java Heap Size for ElasticSearch Nodes

**URL:** <https://discuss.elastic.co/t/java-heap-size-for-elasticsearch-nodes/252178>\
**Category:** Elasticsearch\
**Created:** [October 15, 2020, 11:05am UTC](https://discuss.elastic.co/t/java-heap-size-for-elasticsearch-nodes/252178 "2020-10-15T11:05:08Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![gizem](https://avatars.discourse-cdn.com/v4/letter/g/7ea924/32.png) [@gizem](https://discuss.elastic.co/u/gizem)\
**Post date:** [October 15, 2020, 11:05am UTC](https://discuss.elastic.co/t/java-heap-size-for-elasticsearch-nodes/252178/1 "2020-10-15T11:05:08Z")

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Hello,  
I have an elasticsearch cluster with two nodes. I have read that java heap size sould not be more than 50% of physical memory. Is it valid for sum of all nodes heap size or just one?

For instance, my computer's physical memory is 24Gb. If I set 12Gb java heap size for **each node** , is it true?

Thank you,  
Gizem

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**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [October 15, 2020, 11:26am UTC](https://discuss.elastic.co/t/java-heap-size-for-elasticsearch-nodes/252178/2 "2020-10-15T11:26:23Z")

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You should run **only one node** with 12gb of heap.

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**Author:** ![gizem](https://avatars.discourse-cdn.com/v4/letter/g/7ea924/32.png) [@gizem](https://discuss.elastic.co/u/gizem)\
**Post date:** [October 15, 2020, 1:21pm UTC](https://discuss.elastic.co/t/java-heap-size-for-elasticsearch-nodes/252178/3 "2020-10-15T13:21:19Z")

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Thank you @dadoonet, but I am confused. Did you mean 2 node cluster is unneccessary or 12gb + 12gb is Ok?

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**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [October 15, 2020, 1:22pm UTC](https://discuss.elastic.co/t/java-heap-size-for-elasticsearch-nodes/252178/4 "2020-10-15T13:22:39Z")

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I'm saying that you should not run 2 nodes on the same machine.

Unless you have more than 64gb of RAM on the machine.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [November 12, 2020, 1:22pm UTC](https://discuss.elastic.co/t/java-heap-size-for-elasticsearch-nodes/252178/5 "2020-11-12T13:22:55Z")

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