# Java virtual memory usage

**URL:** <https://discuss.elastic.co/t/java-virtual-memory-usage/74556>\
**Category:** Elasticsearch\
**Created:** [February 9, 2017, 8:01pm UTC](https://discuss.elastic.co/t/java-virtual-memory-usage/74556 "2017-02-09T20:01:06Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![John16](https://avatars.discourse-cdn.com/v4/letter/j/ea666f/32.png) [@John16](https://discuss.elastic.co/u/John16)\
**Post date:** [February 9, 2017, 8:01pm UTC](https://discuss.elastic.co/t/java-virtual-memory-usage/74556/1 "2017-02-09T20:01:06Z")

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Hello,

I setup ES cluster and started to load logs into it.  
Almost all parameters are in default except  
`ES_JAVA_OPTS="-Xms10g -Xmx10g"`

I see that virtual memory usage of java process (which runs ES) constantly increases. After about 12 hours of running it consumes 264GB:  
`PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 21619 elastic+ 20 0 0.264t 0.018t 6.657g S 519.3 7.4 2565:39 java`

And it continues to grow.

Is it normal?

Thanks.

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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:** [February 10, 2017, 7:54am UTC](https://discuss.elastic.co/t/java-virtual-memory-usage/74556/2 "2017-02-10T07:54:00Z")

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Yes, see [https://www.elastic.co/guide/en/elasticsearch/reference/5.2/heap-size.html](https://www.elastic.co/guide/en/elasticsearch/reference/5.2/heap-size.html)

That's what the 50% rule is for 🙂

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**Author:** ![John16](https://avatars.discourse-cdn.com/v4/letter/j/ea666f/32.png) [@John16](https://discuss.elastic.co/u/John16)\
**Post date:** [February 10, 2017, 9:27am UTC](https://discuss.elastic.co/t/java-virtual-memory-usage/74556/3 "2017-02-10T09:27:13Z")

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> [@warkolm](#):
>
> That's what the 50% rule is for

I read this chapter. I don't quite understand you: I have 256GB RAM, 10g heap size and (at the moment) 351GB of virtual memory used. Virtual memory usage grows steady after ES startup.

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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:** [February 10, 2017, 9:36am UTC](https://discuss.elastic.co/t/java-virtual-memory-usage/74556/4 "2017-02-10T09:36:42Z")

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Yes, it's the OS caching files.

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**Author:** ![John16](https://avatars.discourse-cdn.com/v4/letter/j/ea666f/32.png) [@John16](https://discuss.elastic.co/u/John16)\
**Post date:** [February 10, 2017, 9:55am UTC](https://discuss.elastic.co/t/java-virtual-memory-usage/74556/5 "2017-02-10T09:55:08Z")

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Ah, yes, I understand now: it is the size of index files which Lucene mmap()s.

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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:** [March 10, 2017, 9:55am UTC](https://discuss.elastic.co/t/java-virtual-memory-usage/74556/6 "2017-03-10T09:55:20Z")

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