# Primary Shards MUCH larger than Replicas

**URL:** <https://discuss.elastic.co/t/primary-shards-much-larger-than-replicas/142664>\
**Category:** Elasticsearch\
**Created:** [August 2, 2018, 12:59am UTC](https://discuss.elastic.co/t/primary-shards-much-larger-than-replicas/142664 "2018-08-02T00:59:28Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![andrew\_rueckert](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/andrew_rueckert/32/31974_2.png) [@andrew\_rueckert](https://discuss.elastic.co/u/andrew_rueckert)\
**Post date:** [August 2, 2018, 12:59am UTC](https://discuss.elastic.co/t/primary-shards-much-larger-than-replicas/142664/1 "2018-08-02T00:59:28Z")

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For larger indices, I'm seeing a pattern where my primary shards are _significantly_ larger than replicas. For example, using the `_cat/shards` API, I'm getting:

```auto
524183765326406aba73345d470e727c-2018-07-30 0 p STARTED 9917382 19.9gb 10.4.0.252 prod-es-data-hot-03e9547ee64f9d19c
524183765326406aba73345d470e727c-2018-07-30 0 r STARTED 9917269 6.6gb 10.4.2.167 prod-es-data-hot-022b8be4866a004c4
524183765326406aba73345d470e727c-2018-07-30 1 p STARTED 9906022 20.5gb 10.4.1.197 prod-es-data-hot-07491395f0bb84af5
524183765326406aba73345d470e727c-2018-07-30 1 r STARTED 9905929 6.5gb 10.4.2.207 prod-es-data-hot-08454b4b222c130ef
524183765326406aba73345d470e727c-2018-07-30 2 p STARTED 9911138 18.5gb 10.4.1.217 prod-es-data-hot-0226703b13afd4fe1
524183765326406aba73345d470e727c-2018-07-30 2 r STARTED 9910932 6.5gb 10.4.0.14 prod-es-data-hot-0c78098bc764541e3
524183765326406aba73345d470e727c-2018-07-30 3 p STARTED 9908133 20.2gb 10.4.0.34 prod-es-data-hot-07f6b364df3787667
524183765326406aba73345d470e727c-2018-07-30 3 r STARTED 9907897 6.6gb 10.4.2.251 prod-es-data-hot-0e9476b7710e99538
524183765326406aba73345d470e727c-2018-07-30 4 p STARTED 9907219 19.5gb 10.4.2.220 prod-es-data-hot-08fb8c2ded8c64e3c
524183765326406aba73345d470e727c-2018-07-30 4 r STARTED 9907181 6.6gb 10.4.1.253 prod-es-data-hot-0d8aff97c8ff29904
524183765326406aba73345d470e727c-2018-07-30 5 p STARTED 9905674 20.1gb 10.4.0.80 prod-es-data-hot-0812c487071e9446f
524183765326406aba73345d470e727c-2018-07-30 5 r STARTED 9905482 6.6gb 10.4.1.218 prod-es-data-hot-055876f71221351ec

```

Given prior usage, I expect each shard to be roughly 6-8 GB, which my replicas are. However, my primaries are three times this size! Is this expected? Is there anything I can do, short of setting the index to RO and doing a force-merge? Having wildly differently sized shards is complicating my efforts to balance disk and CPU usage across my cluster.

I'm currently using ES 6.2.4.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [August 30, 2018, 12:59am UTC](https://discuss.elastic.co/t/primary-shards-much-larger-than-replicas/142664/2 "2018-08-30T00:59:28Z")

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