Help me optimize my Plex server

[roguewave]

Howdy folks, looking for some help figuring out where my bottleneck is / ensuring my server is set up to support as many streams as possible.

Core i7 4770
16 GB RAM
All guest OSs running on Samsung 840 EVO
All NAS storage running on 4TB WD Reds

Host OS is SVR 2012 R2
Only two guest OSs I've got running right now are Ubuntu SVR 14.04 (running SAB, SB, CP, PMS), and guest SVR2012R2 (NAS RAID 6)

Using Dynamic Memory on both VMs - no more than 8 GB total is ever used. I've got two cores allocated to Ubuntu, as I understand Plex transcoding is pretty rough on the processor. However, I've never seen any processor spikes above 25% in HyperV Manager. When I use webmin for Ubuntu, it often shows CPU at 100% usage, though. Not sure where the discrepancy lies.

Since I don't see any redlining system processes, I thought the bottleneck might be in the network. I'm not really sure how much bandwidth transcoded video streams consume, though. I've got a 4 NIC PCI card - if I dedicate one of those physical NICs to Ubuntu, and the motherboard NIC to everything else (management, NAS, etc), would that improve performance?

 

[Just Checking]

I have a couple servers running Plex right now (one is a back-up in case the other drops from the network). I can't say that I am a expert at Plex but I have had a lot of problems I worked through and have some experience.

To summarize, the components that I have found which limit the number of streams are:
1. The format that the video file is saved when transcoded.
2. The CPU Characteristics of the Plex Server which is hosting the Plex.
3. The parameters that you have chosen for your Plex Server (if you have altered those parameters away from the defaults set by Plex).
4. The number of saved files and the capacity of the storage media which contains the metadata for those saved files.
5. For streaming outside your intranet, the upload bandwidth of your internet connection.
6. The amount of RAM in your Plex Server doesn't really have a significant contribution on the number of simultaneous streams once you get above some critical level (depends on your OS and the number of VMs you are running).

According to Plex documentation and the forum, it takes a CPUmark score of about 1500 to stream a 720p video with converted stereo audio without hangups. For 1080p, a CPUmark score of 2000 is recommended. The i7-4770 has a passmark score of 9878 so as a rough estimate, you can stream about 6 video streams at 720p or 4 video stream at 1080p under optimum conditions. If you have other stuff going on (running VM's or transcoding other video files) the actual number of video streams possible is restricted significantly. This is for streaming of simultaneous videos to your internal network over a gigabit ethernet network. If you are streaming wirelessly, your wireless router and receivers are the most important factors in being able to simultaneously stream multiple videos without hangups.

If you are trying to stream videos out on the internet to client devices outside your home intranet, the upload bandwidth is often the limiting factor. I have a 20Mbps upload bandwidth which gives me about 13-15Mbps when I speed test my network. A rule of thumb is that I need about 6Mbps per video stream to get good quality streaming without hangups. My real world testing shows that I can stream 2 - 1080p videos simultaneously or 3 - 720p videos.

If your client devices are set-up to do some transcoding, you may be able to do some direct streaming of the files and transfer the audio portions as AAC or AC3 which takes some of the strain off the Plex Server CPU but doesn't help the bandwidth problem.

In the end, you have to understand the capabilities of the media devices you are streaming to and optimize the entire network and settings to get the most simultaneous streams.