# 3 nodes cluster schema / Split Brain **URL:** \ **Category:** Elasticsearch\ **Created:** [October 28, 2015, 2:13pm UTC](https://discuss.elastic.co/t/3-nodes-cluster-schema-split-brain/33154 "2015-10-28T14:13:28Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![zokratez](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zokratez/32/5974_2.png) [@zokratez](https://discuss.elastic.co/u/zokratez)\ **Post date:** [October 28, 2015, 2:13pm UTC](https://discuss.elastic.co/t/3-nodes-cluster-schema-split-brain/33154/1 "2015-10-28T14:13:28Z")
Hi! I want to know if with this current schema I'm safe from split brain error... Node1: master and data Node2: slave and data Node3: dedicated master Node1 unicast point to Node2 Node2 unicast point to Node3 Node3 unicast point to Node1 Node1: ``` cluster.name: elasticsearch node.name: "node1" node.master: true node.data: true discovery.zen.ping.multicast.enabled: false discovery.zen.ping.unicast.hosts: ["node2"] discovery.zen.minimum_master_nodes: 2 ``` Node2: ``` cluster.name: elasticsearch node.name: "node2" node.master: false node.data: true discovery.zen.ping.multicast.enabled: false discovery.zen.ping.unicast.hosts: ["node3"] discovery.zen.minimum_master_nodes: 2 ``` Node3: ``` cluster.name: elasticsearch node.name: "node3" node.master: true node.data: false discovery.zen.ping.multicast.enabled: false discovery.zen.ping.unicast.hosts: ["node1"] discovery.zen.minimum_master_nodes: 2 ``` The node api show: > node1 127.0.0.1 43 16 9.64 d m node1 > node3 127.0.0.1 6 11 0.15 - \* node3 > node2 127.0.0.1 38 38 1.95 d - node2 And all the indices are green. Anyway... It this configuration a risk to my cluster? Can be better? Thanks! ---
**Author:** ![lwintergerst](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/lwintergerst/32/18164_2.png) [@lwintergerst](https://discuss.elastic.co/u/lwintergerst)\ **Post date:** [October 28, 2015, 2:16pm UTC](https://discuss.elastic.co/t/3-nodes-cluster-schema-split-brain/33154/2 "2015-10-28T14:16:28Z")
You wont get the split brain problem. But running with 2 masters is just as bad as running with just 1. If one of your master nodes fails, the "minimum master node: 2" will make the other nodes unable to form a cluster. i would suggest using three master nodes and leaving the minimum setting as it is. I would also recommend to include all nodes in the unicast.host config ---
**Author:** ![zokratez](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zokratez/32/5974_2.png) [@zokratez](https://discuss.elastic.co/u/zokratez)\ **Post date:** [October 28, 2015, 2:37pm UTC](https://discuss.elastic.co/t/3-nodes-cluster-schema-split-brain/33154/3 "2015-10-28T14:37:14Z")
Thank you for the tip. I change the config to: Node1: ``` cluster.name: elasticsearch node.name: "node1" node.master: true node.data: true discovery.zen.ping.multicast.enabled: false discovery.zen.ping.unicast.hosts: ["localhost", "node2", "node3"] discovery.zen.minimum_master_nodes: 2 ``` Node2: ``` cluster.name: elasticsearch node.name: "node2" node.master: true node.data: true discovery.zen.ping.multicast.enabled: false discovery.zen.ping.unicast.hosts: ["localhost", "node1", "node3"] discovery.zen.minimum_master_nodes: 2 ``` Node3: ``` cluster.name: elasticsearch node.name: "node3" node.master: true node.data: false discovery.zen.ping.multicast.enabled: false discovery.zen.ping.unicast.hosts: ["node1", "node2", "localhost"] discovery.zen.minimum_master_nodes: 2 ``` Is necessary put self host as localhost into unicast host array list? ---
**Author:** ![lwintergerst](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/lwintergerst/32/18164_2.png) [@lwintergerst](https://discuss.elastic.co/u/lwintergerst)\ **Post date:** [October 28, 2015, 4:50pm UTC](https://discuss.elastic.co/t/3-nodes-cluster-schema-split-brain/33154/4 "2015-10-28T16:50:48Z")
No, i think you can leave out the localhost. But all other nodes are important. Looks good to me 🙂 ---
**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:** [October 28, 2015, 9:48pm UTC](https://discuss.elastic.co/t/3-nodes-cluster-schema-split-brain/33154/5 "2015-10-28T21:48:53Z")
You're better off having all 3 as master eligible and keeping min masters at 2. Cause if you lose one master node now, your cluster will be unavailable. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 5, 2017, 11:42pm UTC](https://discuss.elastic.co/t/3-nodes-cluster-schema-split-brain/33154/6 "2017-07-05T23:42:00Z")