# How much clusters must I use in elastic stack?
**URL:** https://discuss.elastic.co/t/how-much-clusters-must-i-use-in-elastic-stack/289735
**Category:** Elasticsearch
**Created:** [November 20, 2021, 5:49am UTC](https://discuss.elastic.co/t/how-much-clusters-must-i-use-in-elastic-stack/289735 "2021-11-20T05:49:51Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@sidharth\_vijayakumar](https://discuss.elastic.co/u/sidharth_vijayakumar)
#### Post date: [November 20, 2021, 5:49am UTC](https://discuss.elastic.co/t/how-much-clusters-must-i-use-in-elastic-stack/289735/1 "2021-11-20T05:49:51Z")
I am confused which approach would be better having single cluster with 12 nodes or having 3 cluster with 4 nodes each in elastic stack. What are the advantages and disadvantages of single cluster? Does elastic charge me for 3 cluster as far as I know they charge for nodes but can someone clarify which would be better approach and which would be cost effective solution?
I am planning to use these nodes in my cluster :
master , data\_content, data\_hot, ingest, ml, remote\_cluster\_client
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### Author:  [@richcollier](https://discuss.elastic.co/u/richcollier)
#### Post date: [November 20, 2021, 7:10pm UTC](https://discuss.elastic.co/t/how-much-clusters-must-i-use-in-elastic-stack/289735/2 "2021-11-20T19:10:27Z")
It depends.
The license tiers are described here:[Subscriptions | Elastic Stack Products & Support | Elastic](https://www.elastic.co/subscriptions)
Since you want to use ML (based on your node type list) - then you will require at least a platinum license.
In general, you can choose whether or not you want to buy node licenses or "capacity-based" licenses. To get "capacity-based" licenses, you need to license at the Enterprise tier, where you buy blocks of ERUs (explained below).
What's the difference?
- In the node model, a licensed node is an instance of the following node types, each of which is **up to** 64GB in size:
\*\* Data nodes
\*\* Dedicated Master nodes
\*\* Nodes used for cross cluster operations
\*\* Dedicated Machine Learning nodes
Keep in mind that a 1 GB data node is taking up the same license as a 64GB data node. The number of clusters in the node-based model sort of does matter. We'll want to have a separate license for each cluster that's in production (non-prod clusters are not licensed).
- In the "capacity-based" model, an ERU (Enterprise Resource Unit) is defined as block of 64GB of capacity. You are free to create one 64GB node, eight 8GB nodes, sixty-four 1GB nodes, whatever. The number of clusters created also doesn't matter.
In general, despite the fact that an ERU at the Enterprise Tier is more expensive than a node at the Platinum tier, the concept of an ERU allows you much more flexibility and also allows you to use one of our orchestration products to help you manage/deploy clusters (either [ECE](https://www.elastic.co/guide/en/cloud-enterprise/current/Elastic-Cloud-Enterprise-overview.html) or [ECK](https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-overview.html))
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [December 18, 2021, 7:11pm UTC](https://discuss.elastic.co/t/how-much-clusters-must-i-use-in-elastic-stack/289735/3 "2021-12-18T19:11:22Z")
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