# Reindex performance

**URL:** <https://discuss.elastic.co/t/reindex-performance/129691>\
**Category:** Elasticsearch\
**Created:** [April 26, 2018, 2:00pm UTC](https://discuss.elastic.co/t/reindex-performance/129691 "2018-04-26T14:00:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Derrick](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/derrick/32/49944_2.png) [@Derrick](https://discuss.elastic.co/u/Derrick)\
**Post date:** [April 26, 2018, 2:00pm UTC](https://discuss.elastic.co/t/reindex-performance/129691/1 "2018-04-26T14:00:36Z")

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Hi,

I am using reindex api to copy data(300K records), but it takes long time(several hours). any idea?

> 

{  
"source": {  
"index": "trades",  
"type": "trade",  
"size": 1000  
},  
"dest": {  
"index": "trades\_day0",  
"version\_type": "internal"  
}  
}

>

---

<div class="post-metadata">

**Author:** ![polyfractal](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/polyfractal/32/48162_2.png) [@polyfractal](https://discuss.elastic.co/u/polyfractal)\
**Post date:** [May 4, 2018, 3:07pm UTC](https://discuss.elastic.co/t/reindex-performance/129691/2 "2018-05-04T15:07:48Z")

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Slow disk IO? 100% cpu utilization? Could just be a hardware bottleneck if the node is very small.

You could try slicing the reindex to speed it up, although I suspect it's a hardware issue.

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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:** [June 1, 2018, 3:07pm UTC](https://discuss.elastic.co/t/reindex-performance/129691/3 "2018-06-01T15:07:50Z")

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