Strange Hyper V Issue

[tworhythms]

I have been evaluating 3CX Version 9 for a couple of weeks now and absolutely love it!

This is my first 3CX install so please bear with me

My setup is as follows:
XEON E5520 with 8GB Ram
Server 2008R2 running Hyper-V on LSI Raid 1
2 TB on dedicated LSI controller in Raid 10 (4 Sata 7200rpm drives)
(2) Cisco SPA504G Phones as well as (2) 3CX Softphones

All of my virtual machines are installed on the Raid 10 drives.
My virtual machines are:
-Domain Controller 1 GB Ram (Server 2008R2) Dedicated 10/100/1000 NIC
-Exchange 2010 4 GB Ram (Server 2008R2) 10/100/1000 Dedicated NIC
-3CX 2GB Ram 10/100/1000 Dedicated NIC

When I try to run 3CX on a fresh 2008R2 Virtual machine the outgoing call quality, IVR and music on hold is fairly poor (i.e. clicking, popping and distorting).

This is where the scenario gets strange:
If I install 3CX on an existing Server 2003 Standard (2 GB 32-Bit version) Virtual using the same virtual switch as the 2008R2 machine and stored on the same Raid 10 setup the audio quality is great. No issues at all.

Also, if I install 3CX directly on the Hyper-V host machine (Server 2008R2) the audio quality is excellent as well.

So, this is what I've tried on the Virtual Server 2008R2 machine:
-Changing the properties of the Virtual and Physical NIC (i.e. IPv4 offloading, buffers, etc...)
-Changing to a different virtual switch
-Implemented QoS on the Server 2008R2 virtual
-Moved the virtual machine to a separate drive with a fixed VHD
-Changed audio codecs, even tried using K-Lite codecs
-Tried assigning 2 processors to the Server 2008R2 virtual instead of 1
-Shut down Exchange 2010 and increased memory allocation to the 3CX virtual (4 GB)
-Desktop experience and Quality Audio Video is installed
-Changed the heartbeat, time syncronization properties of integrated services
-Checked and double checked the firewall settings using the firewall checker
-Used Wireshark to capture and analyze SIP and RTP packets (nothing out of the normal showed up)

On a side note; if I install 3CX on an existing Windows 7 virtual machine using the same virtual switch (virtual NIC) the audio is terrible as well.

So, why is the audio quality so superb while running on the Server 2003 virtual machine as opposed to the Server 2008R2 and Windows 7 virtual machines, especially considering they all use the same virtual switch (not all at the same time though)? This would lead me to believe that the problem is not with networking.

Any help/thoughts would be truly appreciated. While I don't mind running 3CX on the Virtual Server 2003 machine, I would much rather have it running on a current OS (i.e.Server 2008R2).

Thanks everyone!

 

[SY]

To exclude "RTC" from the discussion please try to do following:
1. open 3CXPhoneSystem.ini file and remove semicolon before "Msusetickcount" entry in [General] section. (it is at the beginning of file)
2. save the file
3. restart "media server" service.

If it doesn't alter quality of audio delivery then you need to dig into configuration of "networking"/driver layer of either the host or the Hyper-V virtal machine

Thanks

 

[captivateglobal]

As for other server loads interfering, I'm not so sure. One could test that with the stripped-down, free version of Hyper-V Server 2008 R2 (almost no UI) compared to the full Windows Server 2008 R2 running Hyper-V.

I'm not entirely sure how Hyper-V works, but as I understood the basic Hyper-V software is something you load on top of W2K8's kernel. I would imagine the kernel has virtualization technology in it; however not to the same bare-metal spec as an ESX server.

However I didn't know a product like 'Hyper-V Server 2008 R2' existed - which would probably be much closer in performance to ESX and have less of these kind of issues as a result. If you were to be running a PBX in a virtual environment, the best choice for the hypervisor is the one with the best timing. I must admit I am partial to VMWare as I've been using it since the early days, and I tend to stick with products I know. The same challenges apply across all vendors, of course.

On a side note, I've had some limited success in getting TDM telephony working in a virtualized environment via PCI passthrough, but the RTC is not solid enough to keep sync with something like TDM - SIP/RTP is hard enough!

 

[SY]

Stepan,

Can you explain a little more about the purpose of the "Msusetickcount' entry? How does 3CX interact with the system clock when this value is and is not set?

Thanks,

It is a "safe mode"...

 

[tworhythms]

Great feedback! I've been away on business and just now have been able to read the posts.

The RTC timing sounds like it could be the culprit! It could certainly explain why some people have had absolutely zero problems with the exact same setup and why my Server 2003 worked as well as it did.

Also, it's my understanding that ASUS has used different techniques on their Z8NA-D6 motherboard to achieve the dual Xeon configuration on an ATX from factor (i.e. different length buses to/from the memory controller to correct timing issues). I wonder if some of these hardware modifications could be coming into play as well?

Unfortunately, I have already completely replaced my Hyper-V infrastructure with ESXi so testing this theory is not going to be easy. Is anybody else running this motherboard with Hyper-V and 3CX running Server 2008 64 Bit?

Thanks everyone for the help! These forums are invaluable! If I ever go back to Hyper-V with this setup then I will certainly try these suggestions.