# Use of master-eligible nodes that are not acting as master?

**URL:** <https://discuss.elastic.co/t/use-of-master-eligible-nodes-that-are-not-acting-as-master/205261>\
**Category:** Elasticsearch\
**Created:** [October 25, 2019, 1:16pm UTC](https://discuss.elastic.co/t/use-of-master-eligible-nodes-that-are-not-acting-as-master/205261 "2019-10-25T13:16:12Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![tomhe](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tomhe/32/120065_2.png) [@tomhe](https://discuss.elastic.co/u/tomhe)\
**Post date:** [October 25, 2019, 1:16pm UTC](https://discuss.elastic.co/t/use-of-master-eligible-nodes-that-are-not-acting-as-master/205261/1 "2019-10-25T13:16:12Z")

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From the documentation:

> **[Node | Elasticsearch Guide \[8.11\] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-node.html#master-node)**

> Indexing and searching your data is CPU-, memory-, and I/O-intensive work which can put pressure on a node’s resources. To ensure that your master node is stable and not under pressure, it is a good idea in a bigger cluster to split the roles between dedicated master-eligible nodes and dedicated data nodes.

Our cluster currently consists of 13 nodes, where all nodes are data nodes and nodes 1-4 are master-eligible nodes. We're having performance issues so I'm thinking that maybe it's time to remove the data role from the master-eligible nodes (according to the quoted text above).

Question: If we have four master-eligible nodes that are not data nodes, what use will we have of the three master-eligible nodes that are not acting as the master? Will they add value to the cluster during this time or only be of value as fail-over if the current master goes down and a new master needs to be elected? Will they basically be idle all of the time when another node is acting as master?

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**Author:** ![DavidTurner](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/davidturner/32/22453_2.png) [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)\
**Post date:** [October 26, 2019, 3:40pm UTC](https://discuss.elastic.co/t/use-of-master-eligible-nodes-that-are-not-acting-as-master/205261/2 "2019-10-26T15:40:19Z")

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> [@tomhe](#):
>
> Will they add value to the cluster during this time or only be of value as fail-over if the current master goes down and a new master needs to be elected?

Although the extra master nodes won't necessarily be using all their resources at all times, that doesn't mean they are not valuable. There is a great deal of value in having enough redundancy in your systems to cope with inevitable outages.

Four master-eligible nodes are no more useful than three, however, because both configurations can tolerate the loss of just one master-eligible node. I would recommend sticking with three. You could also try having just two dedicated master-eligible nodes together with a [voting-only master-eligible node](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-node.html#voting-only-node) which could reasonably be one of your data nodes.

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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:** [November 23, 2019, 3:40pm UTC](https://discuss.elastic.co/t/use-of-master-eligible-nodes-that-are-not-acting-as-master/205261/3 "2019-11-23T15:40:20Z")

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