# High availability cluster settings

**URL:** <https://discuss.elastic.co/t/high-availability-cluster-settings/12416>\
**Category:** Elasticsearch\
**Created:** [June 14, 2013, 12:34pm UTC](https://discuss.elastic.co/t/high-availability-cluster-settings/12416 "2013-06-14T12:34:28Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Runar\_Myklebust](https://avatars.discourse-cdn.com/v4/letter/r/a6a055/32.png) [@Runar\_Myklebust](https://discuss.elastic.co/u/Runar_Myklebust)\
**Post date:** [June 14, 2013, 12:34pm UTC](https://discuss.elastic.co/t/high-availability-cluster-settings/12416/1 "2013-06-14T12:34:28Z")

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Hi.

We have elasticsearch embedded in our product.

Most customers are asking for cluster settings ensuring high availability,  
that is:

In a scenario with 4 servers, they want to make sure that if 3 of the 4  
nodes goes down, the last one should be able to handle requests (and also  
write-operations)

What is the best way to accomplish this? Query performance is usually not a  
big issue, since the amount of data is limited to, say, 300.000 documents.  
Also, there are not many write-operations done except when doing a manual  
reindex of all documents (usually just once)

A possible solution is to run with 1 shard / 3 replicas, and set the  
write\_consistency to "one". This will ensure that all nodes always has the  
data necessary to serve and also be able to write to index. This does  
implicate that its not possible for one node to be accessible without  
having contact with the other nodes.

For other customers, they may have 12 nodes, 6 nodes in two different  
locations. The main priority here will also be that "as few as possible"  
nodes needs be running at the same, and still work. Also, here - a scenario  
where one of the locations is down while all nodes in the other locations  
will be available.

Any thought around this?

## greetings

Runar Myklebust

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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, 2:31am UTC](https://discuss.elastic.co/t/high-availability-cluster-settings/12416/2 "2017-07-06T02:31:15Z")

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