How I converted to paravirtual SCSI controllers from LSI March 30, 2011Posted by Brent Quick in : vSphere 4.1 , trackback
Looking at having moved from vSphere 4.0 to 4.1 I was interested in what knobs I might turn to get more performance out of my vm environment which consists of the following IBM x3650, x3650 M3, and DS3400 FC SAN with 15K SAS drives. This led me to look at the higher performance paravirtual SCSI controllers instead of the existing LSI controllers. Enhanced in update 1 to support boot disks it seemed like time to give them a try, but how to convert my existing LSI controllers to paravirtual?First a little background on the paravirtual SCSI controller from VMware KB article 1010398 which discusses how to add a paravirtual controller to an existing build.
Problem with that KB is that I do not want to add another controller but simply convert my existing. So after a couple of BSOD’s and some Safe Mode OS boots, I figured out the trick. (Here is Alan Renouf’s Xtravirt article on how to do it which I found after the fact when researching for this post)
Add an additional disk – say 10 MB – but make sure that the virtual device node is 1:0 or greater so that VMware will add a new controller. If you do not have a floppy device attached to your vm add that as well and set the device type to a floppy image in the data store. Once the controller is added set that controller to be a paravirtual type and boot the vm. Windows should find the device and add the driver but if not then perform normal steps to add it. Once confirmed as being loaded (device manager) you can shut down the vm. Now you are in the home stretch, simple remove the other hard drive (which removes the other controller) and switch the existing LSI to paravirtual (click on the controller and then the change type button) and boot the vm. If all things operate as they should you should see your server boot normally.
Note: This is for Windows only since I am not running any flavors of Linux, but the KB article does cover several distro’s.