# Do Replicas take up memory?

**URL:** <https://discuss.elastic.co/t/do-replicas-take-up-memory/25375>\
**Category:** Elasticsearch\
**Created:** [July 12, 2015, 1:47am UTC](https://discuss.elastic.co/t/do-replicas-take-up-memory/25375 "2015-07-12T01:47:59Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![James\_Harbal](https://avatars.discourse-cdn.com/v4/letter/j/7993a0/32.png) [@James\_Harbal](https://discuss.elastic.co/u/James_Harbal)\
**Post date:** [July 12, 2015, 1:47am UTC](https://discuss.elastic.co/t/do-replicas-take-up-memory/25375/1 "2015-07-12T01:47:59Z")

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I am trying to figure out whether replicas take up as much memory as primary shards, or do they just require a little bit of overhead?

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**Author:** ![nik9000](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/nik9000/32/44947_2.png) [@nik9000](https://discuss.elastic.co/u/nik9000)\
**Post date:** [July 12, 2015, 3:43am UTC](https://discuss.elastic.co/t/do-replicas-take-up-memory/25375/2 "2015-07-12T03:43:07Z")

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As much as primary shards. Same amount of space too.

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**Author:** ![James\_Harbal](https://avatars.discourse-cdn.com/v4/letter/j/7993a0/32.png) [@James\_Harbal](https://discuss.elastic.co/u/James_Harbal)\
**Post date:** [July 12, 2015, 4:09am UTC](https://discuss.elastic.co/t/do-replicas-take-up-memory/25375/3 "2015-07-12T04:09:11Z")

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So it has to put into memory all of the parent/child and index information into memory for each primary and replica shard?

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**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [July 12, 2015, 7:33am UTC](https://discuss.elastic.co/t/do-replicas-take-up-memory/25375/4 "2015-07-12T07:33:27Z")

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Yes. A replica is exactly the same and acts the same as a primary.

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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, 12:02am UTC](https://discuss.elastic.co/t/do-replicas-take-up-memory/25375/5 "2017-07-06T00:02:08Z")

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