# Use ILM to reduce the size of an existing index

**URL:** <https://discuss.elastic.co/t/use-ilm-to-reduce-the-size-of-an-existing-index/284709>\
**Category:** Elasticsearch\
**Tags:** ilm-index-lifecycle-management\
**Created:** [September 21, 2021, 11:13am UTC](https://discuss.elastic.co/t/use-ilm-to-reduce-the-size-of-an-existing-index/284709 "2021-09-21T11:13:41Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![goncalobsantos](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/goncalobsantos/32/50118_2.png) [@goncalobsantos](https://discuss.elastic.co/u/goncalobsantos)\
**Post date:** [September 21, 2021, 11:13am UTC](https://discuss.elastic.co/t/use-ilm-to-reduce-the-size-of-an-existing-index/284709/1 "2021-09-21T11:13:41Z")

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I have an index that has grown too much and am trying to understand if the index lifecycle management can help me with this problem.

The index is approaching the size of 50 GB. From what I have read, I could use ilm to define a policy to create a new index after the 50 GB limit is reached.

But is there a way to split the existing index in smaller chunks using the ilm? Idealy, I would like to split it in 10 chunks with 5 GB each and then define a policy that creates new indexes after the 5 GB limit is reached.

If possible, could you please direct me to the relevant documentation? Thank you.

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**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [September 21, 2021, 10:27pm UTC](https://discuss.elastic.co/t/use-ilm-to-reduce-the-size-of-an-existing-index/284709/2 "2021-09-21T22:27:07Z")

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You can use the [`_split`](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-split-index.html) endpoint to do this for an existing index, but it does that on a shard level, not into different indices.  
The only way to do this for an existing index would be to reindex.

Also 5GB per index is small, we'd recommend aiming for larger than that to maximise resources.

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**Author:** ![goncalobsantos](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/goncalobsantos/32/50118_2.png) [@goncalobsantos](https://discuss.elastic.co/u/goncalobsantos)\
**Post date:** [September 22, 2021, 10:57am UTC](https://discuss.elastic.co/t/use-ilm-to-reduce-the-size-of-an-existing-index/284709/3 "2021-09-22T10:57:37Z")

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Thanks Marc!

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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:** [October 20, 2021, 10:58am UTC](https://discuss.elastic.co/t/use-ilm-to-reduce-the-size-of-an-existing-index/284709/4 "2021-10-20T10:58:11Z")

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