# Understanding Jvm memory calculation with docker

**URL:** <https://discuss.elastic.co/t/understanding-jvm-memory-calculation-with-docker/276628>\
**Category:** Elasticsearch\
**Tags:** docker\
**Created:** [June 22, 2021, 9:24am UTC](https://discuss.elastic.co/t/understanding-jvm-memory-calculation-with-docker/276628 "2021-06-22T09:24:21Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![marcs42](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@marcs42](https://discuss.elastic.co/u/marcs42)\
**Post date:** [June 22, 2021, 9:24am UTC](https://discuss.elastic.co/t/understanding-jvm-memory-calculation-with-docker/276628/1 "2021-06-22T09:24:22Z")

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I'm having issues understanding the memory requirements. Hope somebody can shine some lights on this.

**Situation:**

- 1 single machine with 20GB ram
- Base OS ubuntu 20.04 LTS
- Runs docker containers of Elasticsearch, Logstash, Kibana, NGINX, Jupyter and Neo4j
- Only ES and Neo4j containers have larger memory demands, and I want to give them as much as possible as it would improve speed for those
- I manually appoint the Neo4j docker container 5GB of memory.
- I've read all the Elasticsearch docker memory advise from [Install Elasticsearch with Docker | Elasticsearch Guide [7.13] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/docker.html)
- I set the `vm.max_map_count`, increased `ulimit` and disabled swapping per container `bootstrap.memory_lock=true" --ulimit memlock=-1:-1`
- I'm aware of the guidance "_Set `Xms` and `Xmx` to no more than 50% of your total memory"_ from here: [Advanced configuration | Elasticsearch Guide [7.13] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/advanced-configuration.html#set-jvm-heap-size)
- I've tried letting docker manage the jvm memory (default recommendation from link above).
- Im getting heap out of memory errors that crash Elasticsearch. At the same time Im seeing OOM-killer messages in `dmesg` , so it seems Elasticsearch is consuming more mem than the kernel allows it.
- I'm also having an installation with same configuration where this is absolutely no issue at all. This is what surprises me the most.

**Questions**  
I've got two major questions, although any advice around jvm settings may help me.

Question 1: Is the docker auto jvm setting smart enough to understand there are also other containers running that require (significant) memory - neo4j in my case, and will it allocate the correct jvm heap size automatically?

Question 2: If I should I set the jvm heap size manually, Im a bit lost on hoe the 50% rule applies. Should Elasticsearch get 50% of total system memory (10GB or 20GB), or 50% of remaining memory after Elasticsearch, Kibana and especially Neo4j dockers containers?

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**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:** [June 22, 2021, 11:00pm UTC](https://discuss.elastic.co/t/understanding-jvm-memory-calculation-with-docker/276628/2 "2021-06-22T23:00:05Z")

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Welcome to our community! 😃

I don't believe the automatic calculations look at what else is running, just the total heap size. (We don't recommend running Elasticsearch alongside multiple other apps like that.)

In your case I would just set the heap manually, make it 6GB and then leave the rest for your other processes and the OS.

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**Author:** ![marcs42](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@marcs42](https://discuss.elastic.co/u/marcs42)\
**Post date:** [June 23, 2021, 9:06am UTC](https://discuss.elastic.co/t/understanding-jvm-memory-calculation-with-docker/276628/3 "2021-06-23T09:06:33Z")

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This gives enough direction to further investigate. Thanks!

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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:** [July 21, 2021, 9:06am UTC](https://discuss.elastic.co/t/understanding-jvm-memory-calculation-with-docker/276628/4 "2021-07-21T09:06:50Z")

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