# Basic question on ES

**URL:** <https://discuss.elastic.co/t/basic-question-on-es/7222>\
**Category:** Elasticsearch\
**Created:** [April 4, 2012, 7:37am UTC](https://discuss.elastic.co/t/basic-question-on-es/7222 "2012-04-04T07:37:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Sushis](https://avatars.discourse-cdn.com/v4/letter/s/bc79bd/32.png) [@Sushis](https://discuss.elastic.co/u/Sushis)\
**Post date:** [April 4, 2012, 7:37am UTC](https://discuss.elastic.co/t/basic-question-on-es/7222/1 "2012-04-04T07:37:37Z")

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Hi,  
I'm just a trainee in a french company and they asks me to use ElasticSearch.  
After reading lot of lines from the official WebSite i've little question :

What is the  
"number\_of\_shards"  
"number\_of\_replicas"

I don't understand what they do and how they do.

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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 6, 2017, 3:33am UTC](https://discuss.elastic.co/t/basic-question-on-es/7222/2 "2017-07-06T03:33:45Z")

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Closed on July 6, 2017, 3:33am UTC