From vSphere U1, VMware now support booting from a Paravirtualized SCSI adapter, why would you want to do this?  Well why not, check out the VMware Performance Blog where VMware have tested this adapter and shared their results.

VMware were able to achieve 350,000 I/O operations per second on a single vSphere host (ESX 4.0) and 3 virtual machines.  From their findings the VMware Paravirtual SCSI (PVSCSI) adapter was able to achieve 12% more throughput with 18% less CPU cost compared to the LSI virtual adapter… Now you see why we should use it!

So in trying to test this the first thing I did was move one of my current virtual machines onto the adapter by clicking “edit settings” go to “SCSI controller 0” and click the change type button, from there you can select “VMware Paravirtual”.

When booting the VM you may find a slight issue though..

A ‘Blue Screen of Death’ welcomes you!

VMtools was installed and at the latest version (U1) but although the PVSCSI driver is shipped with VMtools it is not actually active until you add a PVSCSI adapter to the VM so to enable the PVSCSI driver for the boot device we need a slight bit of trickery….

-->the rest is on Xtravirt site :

http://xtravirt.com/boot-from-paravirtualized-scsi-adapter