Wowza Community

8000MB heap size


We have 16GB Ram on our server. Following the tuning information that Wowza provides, we have set the Java heap size to 8000 MB.

Apologies for the newbie question, but what is this 8000MB used for?

Do videos get cached in this 8000M?




Wowza does use this memory to cache the chunks for “live” HTTP streaming.

This is done on a per stream basis, the default is 10 chunks with a duration of 10 seconds each and this is for each HLS client type you have configured the server to support.

You can adjust these using the guides below:

How to configure Adobe HTTP Dynamic Streaming packetization (sanjosestreaming)

How to configure Apple HTTP Live Streaming packetization (cupertinostreaming)

How to configure Microsoft Smooth Streaming packetization (smoothstreaming)

How to configure MPEG-DASH packetization (mpegdashstreaming)

The memory is also used to hold information on streams, so publishers, video/audio data and java object data. Ensure you enable the garbage collection settings too.

Wowza Streaming Engine 4 does auto tuning based on the hardware it has available to it. Please find the guide below for your convenience.

How to do performance tuning

After editing any tuning configuration you will need to restart Wowza for the changes to take effect.



Are you trying to mitigate a poor encoder uplink, or poor playback connections? If that is the case, there isn’t really anything you can do except provide ABR stream set for playback or reduce the bitrate of the live stream


Thanks Jason,

We use RTMP. Is there any caching that occurs on the server when RTMP streaming?

Are there are parameters which can be used to control the amount of caching?

The issue we have is that we only have one disk, but we have lots of memory. So caching will help us a lot.