# Difference in Primary and Replica Shards **URL:** \ **Category:** Elasticsearch\ **Created:** [October 12, 2018, 6:42am UTC](https://discuss.elastic.co/t/difference-in-primary-and-replica-shards/152167 "2018-10-12T06:42:51Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Sagar\_Arora](https://avatars.discourse-cdn.com/v4/letter/s/3ab097/32.png) [@Sagar\_Arora](https://discuss.elastic.co/u/Sagar_Arora)\ **Post date:** [October 12, 2018, 6:42am UTC](https://discuss.elastic.co/t/difference-in-primary-and-replica-shards/152167/1 "2018-10-12T06:42:51Z")
Stack Details: ElasticSearch/logstash/kibana/X-pack Version : 6.2.3 Cluster Details : 3 Master node , 4 Hot data node , 1 Warm data node Master Node Conf : **Master Node :** [cluster.name](http://cluster.name):ELK [node.name](http://node.name): ELK-ES7 path.data: /elasticsearch/data path.logs: /elasticsearch/logs bootstrap.memory\_lock: true network.host: 1.4.5.6 node.data: false node.master: true discovery.zen.ping.unicast.hosts: ["1.2.3.4", "4.3.2.1", "5.6.7.8"] discovery.zen.minimum\_master\_nodes: 2 xpack.security.enabled: false node.ingest: false action.destructive\_requires\_name: true thread\_pool: index: size: 4 queue\_size: 2000 thread\_pool.bulk.queue\_size: 5000 bootstrap.system\_call\_filter: false Data Node: [cluster.name](http://cluster.name): ELK [node.name](http://node.name): ELK-ES1-new path.data: /elasticsearch/data path.logs: /elasticsearch/logs bootstrap.memory\_lock: true network.host: 1.9.7.8 node.data: true node.master: false discovery.zen.ping.unicast.hosts: ["1.2.3.4", "4.3.2.1", "5.6.7.8"] discovery.zen.minimum\_master\_nodes: 2 xpack.security.enabled: false action.destructive\_requires\_name: true thread\_pool: index: size: 12 queue\_size: 2000 thread\_pool.bulk.queue\_size: 7000 bootstrap.system\_call\_filter: false node.attr.box\_type: hot System Details: 32cores and 64Gb Ram with 3.2Tb SSD : Data node 32cores and 64Gb Ram with 50TB Spinning Disk : Data node Issue Details : 1. Index Size are increasing in gap of days , we can see 2x/3x size of index every alternate days this is causing disk watermark , have checked there is no increase in log size as well still index size are increasing day by day. 2. There is difference between size of Primary shards and replica shards for the same index this is also causing disk watermark and eventually leading to read only mode 3. Have also observed highly unequal shard sizes within an index. ---
**Author:** ![nhat](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/nhat/32/22170_2.png) [@nhat](https://discuss.elastic.co/u/nhat)\ **Post date:** [October 12, 2018, 4:37pm UTC](https://discuss.elastic.co/t/difference-in-primary-and-replica-shards/152167/2 "2018-10-12T16:37:07Z")
This is a known issue ([https://github.com/elastic/elasticsearch/pull/30244](https://github.com/elastic/elasticsearch/pull/30244)), and it was addressed in 6.3.0+. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [November 9, 2018, 4:37pm UTC](https://discuss.elastic.co/t/difference-in-primary-and-replica-shards/152167/3 "2018-11-09T16:37:07Z")
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