ElasticSearch: Replicas of shards only?

2
votes

I have 2 nodes in my ElasticSearch cluster with 1 index. The index is setup to have 5 shards, and 1 replica. I want all 5 shards to be in 1 node, with a replica of each in another node. I don't want ElasticSearch to distribute those 5 shards equally among the 2 nodes (and distribute the replicas equally as well).

In other words, I want 1 node to act strictly as a backup, holding ALL the replicas. Is this possible with ElasticSearch? If so, what settings do I need to configure?

1
elasticsearch
What you describe seems to be against ElasticSearch's default behaviour/design, at least to me. I guess you are looking at a Master-Slave kind of a setup? – Srikanth Venugopalan
@SrikanthVenugopalan Yep that's precisely what I'm looking for. – Henley

1 Answers

1
votes

AFAIK - Master-slave cannot be done just by using Elastic Search.

Elastic search by design uses a different strategy for resilience (node-node). Here is a document explaining the difference -

http://translate.google.com/translate?hl=en&sl=zh-CN&u=http://www.elasticsearch.cn/guide/concepts/scaling-lucene/replication/&prev=/search%3Fq%3Dmaster%2Bslave%2Belasticsearch

Note - the original document is in elasticsearch.cn, couldn't locate the corresponding English document.

The master-slave concept is something that Solr supports.

That being said, if you need a master-slave setup, I would think of using something like a load-balancer to isolate the 'master' and 'replica' instance of ES.

Also note - you can configure ES to have just worker nodes (that do not hold data, but just process search request).

More about it here -http://www.elasticsearch.org/guide/reference/modules/node/