# Internode connection in sIngle primary shard with one replica per node?

**URL:** <https://discuss.elastic.co/t/internode-connection-in-single-primary-shard-with-one-replica-per-node/128095>\
**Category:** Elasticsearch\
**Created:** [April 16, 2018, 1:44am UTC](https://discuss.elastic.co/t/internode-connection-in-single-primary-shard-with-one-replica-per-node/128095 "2018-04-16T01:44:51Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Jason\_Woo](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jason_woo/32/135199_2.png) [@Jason\_Woo](https://discuss.elastic.co/u/Jason_Woo)\
**Post date:** [April 16, 2018, 1:44am UTC](https://discuss.elastic.co/t/internode-connection-in-single-primary-shard-with-one-replica-per-node/128095/1 "2018-04-16T01:44:51Z")

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From reading the Definitive Guide, I learned that the coordinating node forwards a read request to a different shard copy (assuming multiple primary shards and nodes).

- [https://www.elastic.co/guide/en/elasticsearch/guide/2.x/distrib-read.html](https://www.elastic.co/guide/en/elasticsearch/guide/2.x/distrib-read.html)
- [https://www.elastic.co/guide/en/elasticsearch/guide/2.x/distrib-multi-doc.html](https://www.elastic.co/guide/en/elasticsearch/guide/2.x/distrib-multi-doc.html)

How does it work if I have a cluster with single primary shard and one replica per node?  
"settings": { "number\_of\_shards": 1, "auto\_expand\_replicas" : "0-all" }

Each node will have all the data, so there is no need to forward request to get data from another shard. Furthermore, since coordinating node can be round-robin'd, distributing the load also isn't an issue.

In such such set-up, will there be internode communication for read requests?

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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:** [April 16, 2018, 1:52am UTC](https://discuss.elastic.co/t/internode-connection-in-single-primary-shard-with-one-replica-per-node/128095/2 "2018-04-16T01:52:23Z")

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Yes, it will still round robin between the two shards.

If you don't want that, look at [https://www.elastic.co/guide/en/elasticsearch/reference/6.2/search-request-preference.html](https://www.elastic.co/guide/en/elasticsearch/reference/6.2/search-request-preference.html)

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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:** [May 14, 2018, 1:52am UTC](https://discuss.elastic.co/t/internode-connection-in-single-primary-shard-with-one-replica-per-node/128095/3 "2018-05-14T01:52:29Z")

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