CODEWITHSUNDEEP
elasticsearch
ethan.hunt
ethan.hunt

Reputation: 11

How sharding works in elasticsearch

I have "2" "number_of_shards" and "0" "number_of_replicas" to my index. Then how the 2 shards are distributed across 3 nodes if i have 3 nodes cluster.How sharding works in elasticsearch.

Upvotes: 0

Views: 1307

Answers (1)

Alcanzar
Alcanzar

Reputation: 17155

If you have 2 shards and 0 replicas with 3 nodes, one node will have nothing on it.

Sharding works by dividing your ID space into equal parts (based on a hash of your id keys so as to randomize it and not get hot spots). From there the shards are distributed to nodes based on a number of critria (minimizing the number of shards for a given index on a node, available disk space, etc).

Replicas are there to help with read scaling and data recovery if there's an issue.

All queries are then divided into # of shards parts and a map/reduce operation is done to query/combine the results into the final product that you are getting back.

Upvotes: 2

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