# Number of shards per host

**URL:** <https://discuss.elastic.co/t/number-of-shards-per-host/35751>\
**Category:** Elasticsearch\
**Created:** [November 27, 2015, 11:50am UTC](https://discuss.elastic.co/t/number-of-shards-per-host/35751 "2015-11-27T11:50:11Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![abhijith\_reddy](https://avatars.discourse-cdn.com/v4/letter/a/977dab/32.png) [@abhijith\_reddy](https://discuss.elastic.co/u/abhijith_reddy)\
**Post date:** [November 27, 2015, 11:50am UTC](https://discuss.elastic.co/t/number-of-shards-per-host/35751/1 "2015-11-27T11:50:11Z")

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How does one decide the number of hosts ? I understand the answer for such questions is always "It Depends" but is there a strategy to that I can use to determine this number ? I went through this document - [https://www.elastic.co/guide/en/elasticsearch/guide/current/capacity-planning.html](https://www.elastic.co/guide/en/elasticsearch/guide/current/capacity-planning.html) and it recommends to do a test to determine the number of primary shards (index size / max shard size once I have the number what would be a good way to find the number of shards that can be distributed to a host ? Ideally 1 shard per host would be great but that doesn't seem reasonable given my index size. I presume the performance won't be the same when multiple shards are located on a machine. Any pointers would be helpful.

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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:** [November 27, 2015, 11:23pm UTC](https://discuss.elastic.co/t/number-of-shards-per-host/35751/2 "2015-11-27T23:23:26Z")

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How big is your index size?

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**Author:** ![abhijith\_reddy](https://avatars.discourse-cdn.com/v4/letter/a/977dab/32.png) [@abhijith\_reddy](https://discuss.elastic.co/u/abhijith_reddy)\
**Post date:** [November 28, 2015, 9:57am UTC](https://discuss.elastic.co/t/number-of-shards-per-host/35751/3 "2015-11-28T09:57:35Z")

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Index size is around 1.5 TB, we have around 4B documents with 200 shards. We have 10 data nodes and 3 master nodes. Each data node has 48 cores, 144GB of ram with SSD.

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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:** [November 28, 2015, 9:05pm UTC](https://discuss.elastic.co/t/number-of-shards-per-host/35751/4 "2015-11-28T21:05:44Z")

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So 7.5Gb per shard?  
I'd increase that a fair bit, maybe by 5 times.

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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 5, 2017, 11:35pm UTC](https://discuss.elastic.co/t/number-of-shards-per-host/35751/5 "2017-07-05T23:35:10Z")

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