# Shards and replicas allocation in elasticsearch **URL:** \ **Category:** Elasticsearch\ **Created:** [November 15, 2018, 2:51am UTC](https://discuss.elastic.co/t/shards-and-replicas-allocation-in-elasticsearch/156770 "2018-11-15T02:51:54Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![iamlearner123](https://avatars.discourse-cdn.com/v4/letter/i/bcef8e/32.png) [@iamlearner123](https://discuss.elastic.co/u/iamlearner123)\ **Post date:** [November 15, 2018, 2:51am UTC](https://discuss.elastic.co/t/shards-and-replicas-allocation-in-elasticsearch/156770/1 "2018-11-15T02:51:54Z")
Hi, i am new to Elasticsearch and still learning it . can i please how to calculate the number of shards and replicas required for an index ? i now that number factors should be considered but i am kind of confused after reading articles on the internet because some say to use 40% of data node capacity while others use the JVM heap size for calculation shards. For example, i have 9 node cluster with 10GB storage per node and i want index 50 GB of data and JVM size is 32GB. how many shards and replicas do i need ? what is the best practice ?Any detailed explanation would be really helpful . Thank you ---
**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 15, 2018, 4:02am UTC](https://discuss.elastic.co/t/shards-and-replicas-allocation-in-elasticsearch/156770/2 "2018-11-15T04:02:49Z")
> [@iamlearner123](#): > > with 10GB storage per node 10GB, are you sure that is correct? ---
**Author:** ![iamlearner123](https://avatars.discourse-cdn.com/v4/letter/i/bcef8e/32.png) [@iamlearner123](https://discuss.elastic.co/u/iamlearner123)\ **Post date:** [November 15, 2018, 6:02am UTC](https://discuss.elastic.co/t/shards-and-replicas-allocation-in-elasticsearch/156770/3 "2018-11-15T06:02:29Z")
yes.. each node has 10GB storage. ---
**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 15, 2018, 7:28am UTC](https://discuss.elastic.co/t/shards-and-replicas-allocation-in-elasticsearch/156770/4 "2018-11-15T07:28:56Z")
That's a huge heap size for a small amount of data. It's not really efficient. ---
**Author:** ![iamlearner123](https://avatars.discourse-cdn.com/v4/letter/i/bcef8e/32.png) [@iamlearner123](https://discuss.elastic.co/u/iamlearner123)\ **Post date:** [November 15, 2018, 3:28pm UTC](https://discuss.elastic.co/t/shards-and-replicas-allocation-in-elasticsearch/156770/5 "2018-11-15T15:28:05Z")
Thank you for the reply. So, we assign the shards based on the heap size on the node ? What am i trying to understand is that on what factors does assignment of shards and replicas depends? ---
**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 15, 2018, 11:50pm UTC](https://discuss.elastic.co/t/shards-and-replicas-allocation-in-elasticsearch/156770/6 "2018-11-15T23:50:11Z")
Shard count per node, and disk space use. ---
**Author:** ![iamlearner123](https://avatars.discourse-cdn.com/v4/letter/i/bcef8e/32.png) [@iamlearner123](https://discuss.elastic.co/u/iamlearner123)\ **Post date:** [November 19, 2018, 11:37pm UTC](https://discuss.elastic.co/t/shards-and-replicas-allocation-in-elasticsearch/156770/7 "2018-11-19T23:37:04Z")
But in my case i am having a data set of 50GB. Can i please know how many shards to allocate per node and why ? Thank you ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [December 17, 2018, 11:37pm UTC](https://discuss.elastic.co/t/shards-and-replicas-allocation-in-elasticsearch/156770/8 "2018-12-17T23:37:07Z")
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