# Adding new DATA Node on existing Cluster **URL:** \ **Category:** Elasticsearch\ **Created:** [January 2, 2020, 3:13pm UTC](https://discuss.elastic.co/t/adding-new-data-node-on-existing-cluster/213592 "2020-01-02T15:13:21Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![seddikalaouiismaili](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/seddikalaouiismaili/32/87834_2.png) [@seddikalaouiismaili](https://discuss.elastic.co/u/seddikalaouiismaili)\ **Post date:** [January 2, 2020, 3:13pm UTC](https://discuss.elastic.co/t/adding-new-data-node-on-existing-cluster/213592/1 "2020-01-02T15:13:21Z")
Hello Team, I would like to new data node on my existing elk cluster .. Did you know what is the best practices for this pls ? actualy i have two node on my cluster Regards sai ---
**Author:** ![Emanuil](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/emanuil/32/36783_2.png) [@Emanuil](https://discuss.elastic.co/u/Emanuil)\ **Post date:** [January 3, 2020, 12:55am UTC](https://discuss.elastic.co/t/adding-new-data-node-on-existing-cluster/213592/2 "2020-01-03T00:55:11Z")
We recommend an odd number of nodes: 1 or 3 would be better. For our best practices on adding nodes, see [https://www.elastic.co/guide/en/elasticsearch/reference/current/add-elasticsearch-nodes.html](https://www.elastic.co/guide/en/elasticsearch/reference/current/add-elasticsearch-nodes.html) . For setting a node to be a data-only node, see [https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-node.html](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-node.html) . Personally, I wouldn't set node roles (i.e. make them all master and data eligible) for such a small cluster, unless your setup has very specific constraints that make this problematic. ---
**Author:** ![seddikalaouiismaili](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/seddikalaouiismaili/32/87834_2.png) [@seddikalaouiismaili](https://discuss.elastic.co/u/seddikalaouiismaili)\ **Post date:** [January 7, 2020, 3:43pm UTC](https://discuss.elastic.co/t/adding-new-data-node-on-existing-cluster/213592/3 "2020-01-07T15:43:46Z")
> [@Emanuil](#): > > We recommend an odd number of nodes hello, @Emanuil many thanks 🙂 i have another issue !! actualy we have just two node seperated in two datacenter (cluster of 2 nodes). We would add two nodes to make the servers (nodes) lighter. what do you suggest ? add data nodes for example on the exisisting cluster!! Regards sai ---
**Author:** ![Emanuil](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/emanuil/32/36783_2.png) [@Emanuil](https://discuss.elastic.co/u/Emanuil)\ **Post date:** [January 8, 2020, 2:59pm UTC](https://discuss.elastic.co/t/adding-new-data-node-on-existing-cluster/213592/4 "2020-01-08T14:59:07Z")
I'd generally recommend keeping one cluster per data centre and using [Cross-Cluster Search](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-cross-cluster-search.html) . There is also some commercial functionality around this in the form of [Cross Cluster Replication](https://www.elastic.co/guide/en/elasticsearch/reference/current/xpack-ccr.html). Don't you find latency between the nodes is too much of a problem when each node is in a separate data center? I would still make sure there are 3 nodes. The problem with 2 is that you get no redundancy - if one goes down the entire cluster **should** go down. If it's not configured to do that, 2 nodes has the potential for a split brain problem, see [this discuss question for info, especially this answer](https://discuss.elastic.co/t/need-more-clarity-and-understanding-on-split-brain-problem/53184/6) on what to do with 2 nodes. So this is why I would add at least one more node - then one of them can go down and the cluster keep running with 2 out of 3. Overall I definitely wouldn't recommend running a cluster across 2 data centers, the nodes talk _a lot_ between themselves when you're adding data or if a node fails. Unless the 2 centers are right next to each other, you're going to run into serious trouble as you put load on the cluster. ---
**Author:** ![seddikalaouiismaili](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/seddikalaouiismaili/32/87834_2.png) [@seddikalaouiismaili](https://discuss.elastic.co/u/seddikalaouiismaili)\ **Post date:** [January 10, 2020, 10:29am UTC](https://discuss.elastic.co/t/adding-new-data-node-on-existing-cluster/213592/5 "2020-01-10T10:29:33Z")
hi @Emanuil many thanks for your answer 🙂 ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [February 7, 2020, 10:29am UTC](https://discuss.elastic.co/t/adding-new-data-node-on-existing-cluster/213592/6 "2020-02-07T10:29:33Z")
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