Hi @Paul Santos,
Is that 5000 viewers per bitrate, or 5000 viewers total? A rule of thumb for the required bandwidth when using HLS is:
[number of concurrent viewers] x [average bitrate per viewers] x 1.2
That would be 5000 x 1024 x 1.2 = ~6.1 Gbps for the lowest bitrate, or ~18.4Gbps for the highest. In case of the latter, a 10Gbps would obviously not be enough. MPEG-DASH has less overhead, and RTMP/RTSP have barely any overhead, so in that case you can drop the “x 1.2”
I would most certainly tune the Linux kernel, simply Google for it, make sure you find some information that matches a recent Linux kernel (e.g. don’t blindly use optimization tricks for a 2.6 kernel on a 4.x kernel)
I’d also tune Wowza. See e.g. https://www.wowza.com/community/questions/4852/question-aboutsendbuffersizereceivebuffersize.html (post from Roger @ Nov 27 '13 at 6:24 PM) and https://www.wowza.com/docs/tune-wowza-streaming-engine-for-optimal-performance
Also make sure that your Heap Size is tuned. Wowza provides default settings for Development or Production, but you may want to go beyond 10G - also dependent on how many incoming streams you have and if you intend to do transcoding.
Speaking of which, if you have plans for transcoding, then an E5-2620 will barely be enough to transcode into these 4 bitrates, especially if you go Full-HD. If this is only a single stream, then even a consumer-grade NVidia GTX can help, although professional GPUs are recommended. But maybe the CPU will be able to handle this, you’ll have to test. This also depends on if it’s event based (so that the CPU can catch some breathe in between), or if it’s 24/7
The Load Test Tool that Jason recommends here, is a good way to check if you’re server’s ready. Tip: fire up some heavyweight AWS EC2 machines (or corresponding VMs on Azure, Google Cloud, etc.) in different regions and zones, and let them fire away at your server all at once. Since you can stop and optionally terminate these instances directly after your test, it’s a relatively cheap way to get decent hardware and network and you can put some real good pressure on your server from different geographic regions.
Last but not least, out of curiosity: Why do you need to have 5000 viewers on a single server, why not use a CDN, or at least an Origin/Edge?