# Routing: Equal distribution on all shards **URL:** \ **Category:** Elasticsearch\ **Created:** [May 30, 2019, 1:01pm UTC](https://discuss.elastic.co/t/routing-equal-distribution-on-all-shards/183531 "2019-05-30T13:01:42Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![pokaleshrey](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/pokaleshrey/32/48680_2.png) [@pokaleshrey](https://discuss.elastic.co/u/pokaleshrey)\ **Post date:** [May 30, 2019, 1:01pm UTC](https://discuss.elastic.co/t/routing-equal-distribution-on-all-shards/183531/1 "2019-05-30T13:01:42Z")
Hi, I have 5 unique routing keys "a","b","c","d","e" in my application. My ES setup consists of 5 shards. When i check in current state (ver 6.6.2). My shard allocation is like this: ``` a 4 b 2 c 0 d 3 e 4 ``` Note that shard number 1 is unallocated. Shard number 4 is overallocated. **Query** Is there a way that i can ensure all my shards are distributed across 5 shards with one key each ? I understand there is a murmur hash algorithm which is involved in allocation. ---
**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\ **Post date:** [May 30, 2019, 9:47pm UTC](https://discuss.elastic.co/t/routing-equal-distribution-on-all-shards/183531/2 "2019-05-30T21:47:09Z")
The only way to force one allocation key per shard is to specify the routing when indexing things in Elasticsearch. The default routing is based on a hash of the document, rather than a specific key. ---
**Author:** ![pokaleshrey](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/pokaleshrey/32/48680_2.png) [@pokaleshrey](https://discuss.elastic.co/u/pokaleshrey)\ **Post date:** [May 31, 2019, 4:15am UTC](https://discuss.elastic.co/t/routing-equal-distribution-on-all-shards/183531/3 "2019-05-31T04:15:14Z")
Thanks for your reply. I am not using the default routing, while indexing i do specify eg: routing=a. My problem is when i finish indexing for all routing keys i have. Shard 1 remains unallocated. I need a way such that a,b,c,d,e, (having 5 shards in ES), documents for each routing key goes on separate shard. I understand that it totally depends on the hash generate for the given keys. **My base problem:** In above example say routing=a and routing=e goes on same shard i.e. 4. Assume a and e are types of documents, which have few fields in common. When i query documents with routing=a and on common fields, ES also checks all documents in routing=e lowering the performance extensively. [Check this thread](https://discuss.elastic.co/t/structured-hierarchy-repeating-fields-causing-low-performance/182482) _Some issue which i see with shard allocation by routing_ If i have 50shards and have 100 routing keys, it may happen that due to the nature of hash generated, some shards will remain unallocated for ever. _Suggestion_: There could be a routing key to shard number mapping in the settings section which will give this control to the user. Such that user will decide which shard the routing key maps to. ---
**Author:** ![Christian\_Dahlqvist](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/christian_dahlqvist/32/4617_2.png) [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)\ **Post date:** [May 31, 2019, 4:59am UTC](https://discuss.elastic.co/t/routing-equal-distribution-on-all-shards/183531/4 "2019-05-31T04:59:48Z")
At the moment the routing key is hashed instead of the id. If you have large number of routing keys probability will give a reasonably even distribution. If you need more control and have few routing keys instead consider using multiple separate indices instead. ---
**Author:** ![pokaleshrey](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/pokaleshrey/32/48680_2.png) [@pokaleshrey](https://discuss.elastic.co/u/pokaleshrey)\ **Post date:** [May 31, 2019, 5:19am UTC](https://discuss.elastic.co/t/routing-equal-distribution-on-all-shards/183531/5 "2019-05-31T05:19:21Z")
I already have 200 indexes, and the choosing of index based upon some factors is already manually handled in my code. Each index, inside it is having unique types, which i call the routing keys, which i wanted to distribute equally across shards (my original question). This is like Types (routing keys) inside Types (my indexes). I wonder why the control of choosing shard when routing is given, is not handed to user. I think this would add more flexibility in ES and better control to users. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [June 28, 2019, 5:19am UTC](https://discuss.elastic.co/t/routing-equal-distribution-on-all-shards/183531/6 "2019-06-28T05:19:22Z")
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