Another update from the VMQ front, this time with the formal announcement of a declaration of peace.
After a very long struggle – which started in November 2013, not long after the release of Windows Server 2012 R2 – I dare now confirm that VMQ can be re-enabled on Windows 2012 R2 Hyper-V hosts with HP/Emulex 554FLB host bus adapters.
If you have followed along, you will know that we have published several blogs on Hyper-V.nu discussing the matter. We initially discovered the problem in our own lab environment, then explained how to avoid the network disconnections by disabling VMQ, followed by how we tested the numerous HP/Emulex firmware and driver updates and about our interactions with Microsoft, Emulex and to a lesser extent HP. Many customers who were using the HP/Emulex, but also many other using OEM versions, were badly hit by the networking problems. The problem with VMQ became well known all over the world, not to say notoriously known.
Several weeks ago I was able to test a combination of new HP/Emulex firmware and drivers (February 2015), combined with a private Microsoft hotfix (The KB for the final hotfix is KB3031598), provided by the Microsoft Networking team in Redmond. We already saw promising results using older versions, but there were a couple of remaining issues which had to be solved in the Windows NIC Teaming (LBFO) stack. One issue that I kept seeing was that when there were more VMs running on a particular host in the cluster than there were VMQs available, things started to collapse. Not only were the additional VMs not getting a VMQ Queue, they would also not get assigned to the default VMQ Queue. Other VMs that were already assigned to a VMQ Queue, were disconnected and it took some time for this problem to settle and make connections possible again.
Using the latest firmware/drivers with the Microsoft LBFO hotfix solves that problem (amongst others).
It is time to say that we have the worst behind us.