# Cluster setup

**URL:** <https://discuss.elastic.co/t/cluster-setup/13516>\
**Category:** Elasticsearch\
**Created:** [September 9, 2013, 1:35pm UTC](https://discuss.elastic.co/t/cluster-setup/13516 "2013-09-09T13:35:10Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![dpolonsky](https://avatars.discourse-cdn.com/v4/letter/d/ecb155/32.png) [@dpolonsky](https://discuss.elastic.co/u/dpolonsky)\
**Post date:** [September 9, 2013, 1:35pm UTC](https://discuss.elastic.co/t/cluster-setup/13516/1 "2013-09-09T13:35:10Z")

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Hi guys  
We have been using 3 nodes cluster on aws that handled up to 6,000 search requests per second : 1 master node on large instance and 2 data nodes on extra large intsances.  
On each node 50% of RAM was allocated and locked for elastic search.  
Data nodes are connected to elb load balancer and all search requests point to this load balancer

When we tried to add 2 more data nodes to support higher traffic (about 15,000 requests per second) cluster became very unstable and one of nodes constently disconnects when traffic comes to about 8,000 - 9,000. Disconnected node causes overload on other nodes which makes all cluster unusable.

when node gies down we r getting varias exceptions:

1. Caused by: org.elasticsearch.search.SearchContextMissingException: No search context found for id

2. org.elasticsearch.transport.SendRequestTransportException: [master][inet[/1.1.1.1:9300]][discovery/zen/leave] at org.elasticsearch.transport.TransportService.sendRequest(TransportService.java:199)

3. org.elasticsearch.common.util.concurrent.EsRejectedExecutionException: rejected execution of [org.elasticsearch.transport.netty.MessageChannelHandler$RequestHandler]  
at org.elasticsearch.common.util.concurrent.EsAbortPolicy.rejectedExecution(EsAbortPolicy.java:35)

can i set the cluster in a more robust way ?  
thx

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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:** [July 6, 2017, 2:17am UTC](https://discuss.elastic.co/t/cluster-setup/13516/2 "2017-07-06T02:17:30Z")

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