# What is the deciding factor for the number of coordinating only node in a cluster and how to route the requests?

**URL:** <https://discuss.elastic.co/t/what-is-the-deciding-factor-for-the-number-of-coordinating-only-node-in-a-cluster-and-how-to-route-the-requests/326842>\
**Category:** Elasticsearch\
**Created:** [March 2, 2023, 11:50am UTC](https://discuss.elastic.co/t/what-is-the-deciding-factor-for-the-number-of-coordinating-only-node-in-a-cluster-and-how-to-route-the-requests/326842 "2023-03-02T11:50:50Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![pruthvi](https://avatars.discourse-cdn.com/v4/letter/p/f19dbf/32.png) [@pruthvi](https://discuss.elastic.co/u/pruthvi)\
**Post date:** [March 2, 2023, 11:50am UTC](https://discuss.elastic.co/t/what-is-the-deciding-factor-for-the-number-of-coordinating-only-node-in-a-cluster-and-how-to-route-the-requests/326842/1 "2023-03-02T11:50:50Z")

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Hi,

I have a requirement to index 100TB of data per month in ES with ILM.

No. dedicated master nodes – 3 nodes.  
Total no. of hot nodes - 66 nodes.  
Total no. of warm nodes - 216 nodes.  
Above calculations are based on understanding from [link](https://www.elastic.co/blog/benchmarking-and-sizing-your-elasticsearch-cluster-for-logs-and-metrics) -

my use case have targets for search response time so according to [dedicated-master-node](https://www.elastic.co/guide/en/elasticsearch/reference/8.6/modules-node.html#dedicated-master-node) - I should use coordinating only nodes.

My question is -

1. how many no. of coordinating only node needed and what is the hardware requirements, how do we decide it?

As per my understanding from [dedicated-master-node](https://www.elastic.co/guide/en/elasticsearch/reference/8.6/modules-node.html#dedicated-master-node) ,we should not use dedicated master nodes to route requests from clients to the other nodes in the cluster and from [coordinating-only-node](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-node.html#coordinating-only-node) - we should send the bulk indexing request and search request to coordination node.

1. how do we route requests with my case with N number of data nodes and N number of coordination only nodes?

Thanks.

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<div class="post-metadata">

**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 8, 2023, 12:54am UTC](https://discuss.elastic.co/t/what-is-the-deciding-factor-for-the-number-of-coordinating-only-node-in-a-cluster-and-how-to-route-the-requests/326842/2 "2023-03-08T00:54:28Z")

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That's a seriously huge cluster and I would suggest that you instead look to split that up and use CCS to make management a little easier. You should also reach out to us [here](https://www.elastic.co/contact) (or send me a DM and I can make direct intros) and we can put you in contact with some of our solutions architects who can also help you plan this cluster.

> [@pruthvi](#):
>
> As per my understanding from [dedicated-master-node](https://www.elastic.co/guide/en/elasticsearch/reference/8.6/modules-node.html#dedicated-master-node) ,we should not use dedicated master nodes to route requests from clients to the other nodes in the cluster

Yes. Doubly so for your proposed cluster size.

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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 5, 2023, 12:55am UTC](https://discuss.elastic.co/t/what-is-the-deciding-factor-for-the-number-of-coordinating-only-node-in-a-cluster-and-how-to-route-the-requests/326842/3 "2023-04-05T00:55:23Z")

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