# 3 master + data node setup **URL:** \ **Category:** Elasticsearch\ **Created:** [March 15, 2018, 4:08am UTC](https://discuss.elastic.co/t/3-master-data-node-setup/124023 "2018-03-15T04:08:19Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![zidane28](https://avatars.discourse-cdn.com/v4/letter/z/edb3f5/32.png) [@zidane28](https://discuss.elastic.co/u/zidane28)\ **Post date:** [March 15, 2018, 4:08am UTC](https://discuss.elastic.co/t/3-master-data-node-setup/124023/1 "2018-03-15T04:08:20Z")
This question may asked before, but I can't find a definitive answer here... My boss currently ask me to design a ES cluster, but with budget constrain... So a default 3 master-dedicated node and also 5 data-dedicated node is a no go. Lastly my boss asked me: "Why not create a cluster with 3 default ES roles nodes? (Means master + data + client etc) Just set minimum master nodes to 2, then no split brain! Why need dedicated master node to begin with?" I don't even know how to retort to my boss since in my knowledge, the purpose of dedicated master node is to prevent split brain... So here are the questions: 1. Is there any consequences / possible issues arise if I go with the 3 default all-in-one roles nodes as a cluster? 2. Why we need dedicated master nodes to begin with? Appreciate on your helps! ---
**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\ **Post date:** [March 15, 2018, 4:40am UTC](https://discuss.elastic.co/t/3-master-data-node-setup/124023/2 "2018-03-15T04:40:58Z")
I'd say that your boss is right here. On small clusters, 3 nodes in total is enough. And even more, if your data fit, you can also have: 2 "big" master+data nodes 1 small master only node (tie-breaker node with fewer memory) That will reduce your bill even more. ---
**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 15, 2018, 5:12am UTC](https://discuss.elastic.co/t/3-master-data-node-setup/124023/3 "2018-03-15T05:12:23Z")
The idea of dedicated masters is to protect your cluster as much as possible. There's nothing wrong with using the default roles and having 3/5 nodes, you just run a higher risk of the active master being over run by queries or index load and then causing a re-election. ---
**Author:** ![zidane28](https://avatars.discourse-cdn.com/v4/letter/z/edb3f5/32.png) [@zidane28](https://discuss.elastic.co/u/zidane28)\ **Post date:** [March 15, 2018, 6:33am UTC](https://discuss.elastic.co/t/3-master-data-node-setup/124023/4 "2018-03-15T06:33:50Z")
So it means if I set my minimum-master right, let's say in this case is 3 nodes, I should set the value to 2, so even if one of my nodes down, split brain won't happen, am I right? ---
**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\ **Post date:** [March 15, 2018, 7:25am UTC](https://discuss.elastic.co/t/3-master-data-node-setup/124023/5 "2018-03-15T07:25:50Z")
Yes. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [April 12, 2018, 7:25am UTC](https://discuss.elastic.co/t/3-master-data-node-setup/124023/6 "2018-04-12T07:25:59Z")
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