SOLVED cPanel + Hyper-V = slow network ?

Hello all -

I recently migrated a server from an older CentOS box to a Hyper-V install on CentOS 7 (minimal install per the install guide). Since the move, I've noticed ridiculously slow network speeds even between the VM and the host. Everything works but it's very slow.

These are Dell T320 servers running Windows Server 2012 Standard R2, dual 10Gb Broadcom NICs and more than enough CPU power and RAM to run a very basic cPanel install.

Pings to the VM fluctuate between 0 and 200ms, though there is no packetloss. Telnet'ing into the VM on standard ports (like 25 for SMTP) takes few seconds before the server responds. Websites load much slower than before and I can see pages actually render (long drop down lists, for example), whereas they were instant prior to the move.

Googling shows it might be a Virtual Machine Queue issue, but the problem remains with it enabled and disabled. I've updated the drivers to my NICs and even tried some registry entry changes all to no avail. I've also swapped virtual switches assigned to the cPanel VM with no luck.

Other VMs (including another Linux VM) have no network issues. I want to believe this is an issue with my Hyper-V host, but I cannot duplicate the network problems with any other server.

Any ideas on things I could check (both Hyper-V host and the VM itself)?

Thanks in advance.

 

Hi Michael -

Thanks for the update. It turns out it was a VMQ issue. Why the original toggling of the feature didn't work, I don't know, but enabling and disabling it again seems to have fixed the issue.

You can probably lock this thread.

Thanks!