# What are the factors that affect the performance?

**URL:** <https://discuss.elastic.co/t/what-are-the-factors-that-affect-the-performance/80570>\
**Category:** Elasticsearch\
**Created:** [March 30, 2017, 1:20am UTC](https://discuss.elastic.co/t/what-are-the-factors-that-affect-the-performance/80570 "2017-03-30T01:20:22Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![HatBoy](https://avatars.discourse-cdn.com/v4/letter/h/ee7513/32.png) [@HatBoy](https://discuss.elastic.co/u/HatBoy)\
**Post date:** [March 30, 2017, 1:20am UTC](https://discuss.elastic.co/t/what-are-the-factors-that-affect-the-performance/80570/1 "2017-03-30T01:20:22Z")

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Elasticsearch version:5.1.1

Plugins installed: [ik]

JVM version:jdk1.8.0\_11

OS version:CentOS release 6.8 (Final), 2.6.32-642.3.1.el6.x86\_64

Description of the problem including expected versus actual behavior:  
First, I have two same machine， everyone memery is 32G, this is my part of config:  
192.168.1.5 jvm.options:  
-Xms12g  
-Xmx12g  
-XX:+UseConcMarkSweepGC  
-XX:CMSInitiatingOccupancyFraction=75  
-XX:+UseCMSInitiatingOccupancyOnly

192.168.1.6 jvm.options:  
-Xms22g  
-Xmx22g  
-XX:+UseConcMarkSweepGC  
-XX:CMSInitiatingOccupancyFraction=75  
-XX:+UseCMSInitiatingOccupancyOnly

My elasticsearch have about 2 billion document, I use Python script put data to elasticsearch speed about 500 document/s, it is to slow, so I modify the jvm.options config, as follows：  
-Xms22g  
-Xmx22g  
-XX:+UseConcMarkSweepGC  
-XX:CMSInitiatingOccupancyFraction=75  
-XX:+UseCMSInitiatingOccupancyOnly

192.168.1.6 jvm.options:  
-Xms22g  
-Xmx22g  
-XX:+UseConcMarkSweepGC  
-XX:CMSInitiatingOccupancyFraction=75  
-XX:+UseCMSInitiatingOccupancyOnly

A miracle happened: I find the put data speed up to 10000 document /s, It's absolutely amazing！I only modify the jvm memory, Why is there such a big change? Speed increased by 20 times！I do not know why, Does memory have a big impact on performance? Please tell me what happened，Thank you!

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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:** [March 30, 2017, 4:36am UTC](https://discuss.elastic.co/t/what-are-the-factors-that-affect-the-performance/80570/2 "2017-03-30T04:36:26Z")

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The first set of configs show different heap sizes, so it's possible that the node with 12GB was slowing things down.

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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:** [April 27, 2017, 4:36am UTC](https://discuss.elastic.co/t/what-are-the-factors-that-affect-the-performance/80570/3 "2017-04-27T04:36:27Z")

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