# Elasticsearch : Hight disk read + slow indexing

**URL:** https://discuss.elastic.co/t/elasticsearch-hight-disk-read-slow-indexing/223163
**Category:** Elasticsearch
**Created:** [March 11, 2020, 2:46pm UTC](https://discuss.elastic.co/t/elasticsearch-hight-disk-read-slow-indexing/223163 "2020-03-11T14:46:39Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![sfa](https://avatars.discourse-cdn.com/v4/letter/s/bb73d2/32.png) [@sfa](https://discuss.elastic.co/u/sfa)
#### Post date: [March 11, 2020, 2:46pm UTC](https://discuss.elastic.co/t/elasticsearch-hight-disk-read-slow-indexing/223163/1 "2020-03-11T14:46:39Z")

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Hello,  
I am doing a benchmark to index 200GB of simple structered document (without text field, without nested document).  
I Observe periodic degradation on indexing rate during at least one hour and hight disk read io. I use bulk request with refresh\_interval = -1, Monitoring not show cpu or memory problem.  
I suspect flush or merge process but with monitoring (\_stats/merge,flush) i do not see increase of merge or flush.

I use one node with 5 shard, Memory 8GB and 4 cpu (disk hdd).

Here are the monitoring diagrams :

![indexing_time](https://us1.discourse-cdn.com/elastic/original/3X/e/e/eeeee74d3427192d785d18651684b3c59dd62089.jpeg) ![operation_rate](https://us1.discourse-cdn.com/elastic/original/3X/7/2/72da0b1f55697a9567281968ea0c5e0c67d26101.jpeg) ![request_rate](https://us1.discourse-cdn.com/elastic/original/3X/1/1/118877842b5159d3c78a0c2c43e56eb27943caa4.jpeg) ![segment_count](https://us1.discourse-cdn.com/elastic/original/3X/d/8/d8e508aefe08567cb63c74a706d1b0bc9e22c970.jpeg)

How to monitore which process of elasticsearch do massive disk read (80mb/s during long period) ?  
How to improve indexing rate and keep constant indexing rate with elasticsearch?

thanks

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<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: [April 8, 2020, 2:46pm UTC](https://discuss.elastic.co/t/elasticsearch-hight-disk-read-slow-indexing/223163/2 "2020-04-08T14:46:48Z")

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