Day 6 in our continuing series of Hyper-V FAQs, Tips, and Tricks deals with inbox drivers. Some might say that this one is obvious and goes without saying, but I've run into lots of people that have just installed Hyper-V as is, and begun to deploy workloads, so I think it's important to bring this one up in case there are those out there that might skip this important step.
There are primarily two locations I've personally seen where inbox drivers can wreak havoc on a deployment: Network Interface Cards (NICs), and Host Bust Adapters (HBAs). Especially with NICs, I've regularly seen a variety of issues ranging from poor network performance in guest and/or the parent partition to intermittent network failures in the guest and/or parent partition. A lot of these issues have to do with issues around RSS, Offload, Chimney, and other advanced networking features, and it's almost a guarantee that you'll see improvements if you update to the latest network drivers. I've found this to be especially true around 10 Gigabit network cards like the Intel X520.
We've also found issues in early Windows 8 testing with the inbox drivers on our HBAs as well in both the Developer Preview and the Beta, and the first thing we do on a new install now is replace the inbox HBA drivers.
Historically, we've seen these issues in Windows 2008, Windows 2008 R2, and Windows 8, and I see no reason that this will change.
To reiterate, though it's generally a good idea to always update inbox drivers on any physical server you deploy, I've found that it can be more critical on Hyper-V workloads due to the extra things that are going on around virtualized NICs (and in Windows 8, virtual HBAs as well).
This concludes Day 6 of the series. I'll be posting the rest from sunny Las Vegas. If you're heading there this week for MMS 2012, feel free to give me a shout, and don't forget to check out SV-B313 "Hyper-V FAQs, Tips, and Tricks!" on Wednesday at 4PM.
Good Luck, and Happy Virtualizing!