# Question about master nodes and behaviour **URL:** \ **Category:** Elasticsearch\ **Created:** [March 19, 2015, 4:03am UTC](https://discuss.elastic.co/t/question-about-master-nodes-and-behaviour/22751 "2015-03-19T04:03:54Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Gobin\_Sougrakpam](https://avatars.discourse-cdn.com/v4/letter/g/e0b2c6/32.png) [@Gobin\_Sougrakpam](https://discuss.elastic.co/u/Gobin_Sougrakpam)\ **Post date:** [March 19, 2015, 4:03am UTC](https://discuss.elastic.co/t/question-about-master-nodes-and-behaviour/22751/1 "2015-03-19T04:03:54Z")
I'm planning to setup ElasticSearch across two datacentres. I know it is not recommended approach to have the cluster across two data centres, but I wanted an easy way to replicate the data cross site. I have some doubts about how many master nodes I should set up. Scenario 1: Two master eligible nodes. One in each Site. discovery.zen.minimum\_master\_nodes: 2 Site A: Master active If Site A goes down a new master cannot be elected as min master node is set to 2. Question 1: How does site B behave? I believe, no new indexes or documents can be created but the searches can still be carried out. Scenario 2: 3 master eligible nodes. Two in Site A and One in Site B. discovery.zen.minimum\_master\_nodes: 3/2 +1 = 2 Site A: Master active If Site A goes down a new master cannot be elected as min master node is set to 2. Question 2: What kind master configuration can help mitigate such a scenario? Thanks. -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/5525b0c5-600a-4174-a3ab-da17ea63f009%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/5525b0c5-600a-4174-a3ab-da17ea63f009%40googlegroups.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**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 19, 2015, 3:39pm UTC](https://discuss.elastic.co/t/question-about-master-nodes-and-behaviour/22751/2 "2015-03-19T15:39:48Z")
This is one reason why we don't recommend such deployments, no matter what you pick here you risk a split or unavailable cluster. Thus, there's no good answer and you need to decide what site you are willing to live without. On 18 March 2015 at 21:03, Gobin Sougrakpam [gobinsougrakpam@gmail.com](mailto:gobinsougrakpam@gmail.com) wrote: > I'm planning to setup Elasticsearch across two datacentres. I know it is > not recommended approach to have the cluster across two data centres, but I > wanted an easy way to replicate the data cross site. I have some doubts > about how many master nodes I should set up. > > Scenario 1: > Two master eligible nodes. One in each Site. > > discovery.zen.minimum\_master\_nodes: 2 > > Site A: Master active > > If Site A goes down a new master cannot be elected as min master node is > set to 2. > > Question 1: How does site B behave? I believe, no new indexes or documents > can be created but the searches can still be carried out. > > Scenario 2: > 3 master eligible nodes. Two in Site A and One in Site B. > > discovery.zen.minimum\_master\_nodes: 3/2 +1 = 2 > > Site A: Master active > > If Site A goes down a new master cannot be elected as min master node is > set to 2. > > Question 2: What kind master configuration can help mitigate such a > scenario? > > Thanks. > > -- > You received this message because you are subscribed to the Google Groups > "elasticsearch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). > To view this discussion on the web visit > [https://groups.google.com/d/msgid/elasticsearch/5525b0c5-600a-4174-a3ab-da17ea63f009%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/5525b0c5-600a-4174-a3ab-da17ea63f009%40googlegroups.com) > [https://groups.google.com/d/msgid/elasticsearch/5525b0c5-600a-4174-a3ab-da17ea63f009%40googlegroups.com?utm\_medium=email&utm\_source=footer](https://groups.google.com/d/msgid/elasticsearch/5525b0c5-600a-4174-a3ab-da17ea63f009%40googlegroups.com?utm_medium=email&utm_source=footer) > . > For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/CAEYi1X-Cyx7957SqPTgCv7b8RQqD9AV5L32tATRrF19LuqX5QA%40mail.gmail.com](https://groups.google.com/d/msgid/elasticsearch/CAEYi1X-Cyx7957SqPTgCv7b8RQqD9AV5L32tATRrF19LuqX5QA%40mail.gmail.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 6, 2017, 12:25am UTC](https://discuss.elastic.co/t/question-about-master-nodes-and-behaviour/22751/3 "2017-07-06T00:25:35Z")