# Rollover exact definition in ILM policy
**URL:** https://discuss.elastic.co/t/rollover-exact-definition-in-ilm-policy/257542
**Category:** Elasticsearch
**Tags:** ilm-index-lifecycle-management
**Created:** [December 3, 2020, 3:57pm UTC](https://discuss.elastic.co/t/rollover-exact-definition-in-ilm-policy/257542 "2020-12-03T15:57:25Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Travis](https://discuss.elastic.co/u/Travis)
#### Post date: [December 3, 2020, 3:57pm UTC](https://discuss.elastic.co/t/rollover-exact-definition-in-ilm-policy/257542/1 "2020-12-03T15:57:25Z")
Hello all !
In the delete phase of the ILM policy, we can delete x days or x hours from **rollover**.
But what is exactly this "rollover" ? :
- Is it the date when index has been renewed as he reached max size (or documents or age) ?
- What about if I have hot/warm/cold architecture ? Rollover will be when index has been renewed ? Or when index has been shrinked in warm phase ?
Thanks ! 🙂
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### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [December 4, 2020, 1:58am UTC](https://discuss.elastic.co/t/rollover-exact-definition-in-ilm-policy/257542/2 "2020-12-04T01:58:16Z")
Rollover is when it reaches the max limit (age or size) and then creates a new write index under the alias.
It can happen independent of hot/warm/cold, as you can roll indices on a single node for eg.
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### Author:  [@Travis](https://discuss.elastic.co/u/Travis)
#### Post date: [December 4, 2020, 9:14am UTC](https://discuss.elastic.co/t/rollover-exact-definition-in-ilm-policy/257542/3 "2020-12-04T09:14:47Z")
Thanks for this confirmation @warkolm !
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [January 1, 2021, 9:14am UTC](https://discuss.elastic.co/t/rollover-exact-definition-in-ilm-policy/257542/4 "2021-01-01T09:14:57Z")
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