# Did number of replicas effect ES memory utilization

**URL:** <https://discuss.elastic.co/t/did-number-of-replicas-effect-es-memory-utilization/91184>\
**Category:** Elasticsearch\
**Created:** [June 28, 2017, 8:31pm UTC](https://discuss.elastic.co/t/did-number-of-replicas-effect-es-memory-utilization/91184 "2017-06-28T20:31:38Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Eli\_Revach](https://avatars.discourse-cdn.com/v4/letter/e/e9c0ed/32.png) [@Eli\_Revach](https://discuss.elastic.co/u/Eli_Revach)\
**Post date:** [June 28, 2017, 8:31pm UTC](https://discuss.elastic.co/t/did-number-of-replicas-effect-es-memory-utilization/91184/1 "2017-06-28T20:31:39Z")

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Hi ,  
We are facing Old GC's from time to time , i like to know if the amount of replica's has a direct impact on the ES memory utilization (looks to me that the answer is yes ) ?

bottom line , if it can increase chance for Old GC's ?

Thanks

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**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:** [June 28, 2017, 10:46pm UTC](https://discuss.elastic.co/t/did-number-of-replicas-effect-es-memory-utilization/91184/2 "2017-06-28T22:46:37Z")

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Yes but it's more complicated than saying it's double the impact.

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**Author:** ![Eli\_Revach](https://avatars.discourse-cdn.com/v4/letter/e/e9c0ed/32.png) [@Eli\_Revach](https://discuss.elastic.co/u/Eli_Revach)\
**Post date:** [June 29, 2017, 6:14am UTC](https://discuss.elastic.co/t/did-number-of-replicas-effect-es-memory-utilization/91184/3 "2017-06-29T06:14:52Z")

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Thanks Mark .

Can you elaborate on it ?

I will be more specific , on my case .

Assuming my cluster is bigger (many node’s ) one , and we don’t use query routing , so basically each query runs on all cluster nodes.  
ES , will used both replica && primary shards to scale my query’s , in term of memory utilization on a given none for specific primary shard , we may have memory utilization of replica shards from other nodes ( or ,and I don’t know if its doable case , memory utilization of replica from the same node , so the memory will include duplicate data set’s , for the primary + shard of the same data set’s )

Thanks

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<div class="post-metadata">

**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:** [June 29, 2017, 10:08am UTC](https://discuss.elastic.co/t/did-number-of-replicas-effect-es-memory-utilization/91184/4 "2017-06-29T10:08:34Z")

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You are likely to "pay" twice the amount for maintaining shards as you have twice the number. But when you start looking at filter/query/agg caches it really depends on what gets queried where.

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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 27, 2017, 10:08am UTC](https://discuss.elastic.co/t/did-number-of-replicas-effect-es-memory-utilization/91184/5 "2017-07-27T10:08:41Z")

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