# Disallow memory-mapping

**URL:** <https://discuss.elastic.co/t/disallow-memory-mapping/284770>\
**Category:** Elasticsearch\
**Tags:** docker\
**Created:** [September 21, 2021, 10:11pm UTC](https://discuss.elastic.co/t/disallow-memory-mapping/284770 "2021-09-21T22:11:36Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Gotze\_des\_Pobels](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/gotze_des_pobels/32/81960_2.png) [@Gotze\_des\_Pobels](https://discuss.elastic.co/u/Gotze_des_Pobels)\
**Post date:** [September 21, 2021, 10:11pm UTC](https://discuss.elastic.co/t/disallow-memory-mapping/284770/1 "2021-09-21T22:11:36Z")

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Are there any disadvantages of setting

```auto
node.store.allow_mmap=false

```

?

I'm trying to run 3 nodes via docker-compose on a openVZ machine and cant increase max\_map\_count from 65536 to 262144.  
What is the worst that could happen and under what circumstances?

---

<div class="post-metadata">

**Author:** ![mayya](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/mayya/32/83147_2.png) [@mayya](https://discuss.elastic.co/u/mayya)\
**Post date:** [September 23, 2021, 9:00pm UTC](https://discuss.elastic.co/t/disallow-memory-mapping/284770/2 "2021-09-23T21:00:16Z")

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setting allow\_mmap to `false` will make Elasticsearch use [niofs](https://www.elastic.co/guide/en/elasticsearch/reference/current/index-modules-store.html) store type for its indices instead of more efficient memory mapped `mmapfs` store type.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [October 21, 2021, 9:00pm UTC](https://discuss.elastic.co/t/disallow-memory-mapping/284770/3 "2021-10-21T21:00:40Z")

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