# nDVR duration limit and WindowDuration

**URL:** <https://community.wowza.com/t/ndvr-duration-limit-and-windowduration/95827>\
**Category:** Wowza Streaming Engine\
**Created:** [January 16, 2023, 11:56pm UTC](https://community.wowza.com/t/ndvr-duration-limit-and-windowduration/95827 "2023-01-16T23:56:21Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Volodymyr\_Bykov](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@Volodymyr\_Bykov](https://community.wowza.com/u/Volodymyr_Bykov)\
**Post date:** [January 16, 2023, 11:56pm UTC](https://community.wowza.com/t/ndvr-duration-limit-and-windowduration/95827/1 "2023-01-16T23:56:21Z")

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The nDVR documentation says:

```
For example, if you set the WindowDuration value to 3 hours, the recording will be 3 hours long. As time continues past 3 hours but is still less than the 30-hour maximum, the recording will be the last 3 hours and the earliest chunks are deleted as time progresses.

Note: Purged chunks to maintain the WindowDuration amount of time don't count toward the 30-hour maximum.

```

So, what exactly happens when WindowDuration is set to 3 hours, but the stream lasts much longer than 30 hours? Does DVR stop recording after 30 hours? OR Will the recording continue forever, and last 3 hours will always be available?

Also, is WindowDuration limiting the HDD space required for a DVR recording?

The documentation is quite confusing on this matter.

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**Author:** ![Jason\_Tuchler](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/jason_tuchler/32/462_2.png) [@Jason\_Tuchler](https://community.wowza.com/u/Jason_Tuchler)\
**Post date:** [January 17, 2023, 12:24am UTC](https://community.wowza.com/t/ndvr-duration-limit-and-windowduration/95827/2 "2023-01-17T00:24:21Z")

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@Volodymyr_Bykov

Here’s more details on the recording duration with long nDVR recordings:  
[https://www.wowza.com/docs/wowza-ndvr-quick-start-guide#recordingLength](https://www.wowza.com/docs/wowza-ndvr-quick-start-guide#recordingLength)

By having a 3 hour window, this will have a smaller playlist/manifest size and should get you past the 30 hour limit.

Yes, less HD space will be used as it’s being purged outside the window range. Within the window range, it will need to be manually purged when not needed.

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**Author:** ![Volodymyr\_Bykov](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@Volodymyr\_Bykov](https://community.wowza.com/u/Volodymyr_Bykov)\
**Post date:** [January 17, 2023, 6:54am UTC](https://community.wowza.com/t/ndvr-duration-limit-and-windowduration/95827/3 "2023-01-17T06:54:21Z")

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Thank you, Jason.

However, the article does not contain a response to my question.

The behavior I’m expecting is: with 3-hour WindowDuration, the DVR records forever, continuously replacing the last 3 hours of recording. “Get past the 30-hour limit” and “record forever” are two different statements. I would like to know the exact behavior.

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**Author:** ![Dorota\_Szafer-Kwasik](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/dorota_szafer-kwasik/32/1150_2.png) [@Dorota\_Szafer-Kwasik](https://community.wowza.com/u/Dorota_Szafer-Kwasik)\
**Post date:** [January 17, 2023, 7:24am UTC](https://community.wowza.com/t/ndvr-duration-limit-and-windowduration/95827/4 "2023-01-17T07:24:09Z")

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Hi,  
“the recording continue forever, and last 3 hours will always be available” - here’s how it works.  
We have nonstop streams but only make 3h available in DVR. It works. There is no problem.