Using PVSCSI Driver on Windows Server 2012 VMs

• Matt Liebowitz
• August 9, 2012October 2, 2012
• 8
• 2880

Are you looking to start testing Windows Server 2012 in your vSphere environment and want to utilize the PVSCSI driver for better potential disk performance and lower CPU utilization?  You may have noticed that the only PVSCSI drivers available for Windows stop at Windows 2008.  But will that work on your Windows 2012 VM?

In short, it sure will!  I gave it a try and can confirm that loading the Windows 2008 PVSCSI driver on your Windows 2012 VM will allow it to load the driver and use the disk.  I’m sure at some point VMware will release an updated version of the driver specific to Windows 2012, but for now this works just fine.

The following post covers how to load the PVSCSI driver on Windows 2012.  If you’ve seen this procedure for Windows 2008 or previous versions then there won’t be any surprises here.

Just like with Windows 2008 (or any other Windows VM), you’ll need to load the correct virtual floppy image that contains the PVSCSI drivers.  In our case, we load the “pvscsi-Windows2008.flp” image in our virtual floppy drive as seen below.

Don’t forget to either select “Connect at power on” on the virtual floppy device or remember to go back in and select “Connected” after the VM has been powered on.

Next, when you boot your VM from the Windows Server 2012 ISO you’ll notice that it is unable to find any hard disks.  Select the Load Driver option to load the driver.

It will scan your virtual floppy disk and report that it found a compatible driver.

Once you select Next, you’ll see that the Windows 2012 installer can correctly read your virtual hard disk.

Finally, once you’re in Windows 2012 you can see in Device Manager (that is, if you can figure out how the heck to launch it) that it reports the correct SCSI controller in Device Manager.

Along with the release of Windows 2012 will be a flood of other new applications to go with it, like Exchange 2013, Lync 2013, and the already released SQL 2012.  Using the PVSCSI driver can help improve performance and lower CPU utilization, especially on workloads that are heavy consumers of disk I/O.  Good to know we won’t have to wait for a newer PVSCSI driver in order to use it on Windows 2012!

Update 10/2/2012 – A comment on this post asked if this still worked on ESXi 5.1, as I actually did the test on ESXi 5.0.  After finally upgrading my home lab I can confirm that this does indeed still work with ESXi 5.1, hardware version 9, and the RTM version of Windows Server 2012.  I’m surprised to see that there isn’t a specifically labeled PVSCSI driver floppy image for Windows Server 2012 in ESXi 5.1, but good to see the Windows 2008 FLP image still works just fine.