New paravirtualized SCSI adapter is more optimized SCSI adapter than the LSI virtual Adapter. This adapter and many more other enhancements are part of new virtual machine hardware version 7 in vSphere 4.
VMware’s new paravirtualized SCSI adapter (pvSCSI) offers 12% improvement in throughput at 18% less CPU cost compared to LSI virtual adapter.
The new pvSCSI is not supported on every OS. Paravirtual SCSI adapters are supported on the following guest operating systems:
– Windows Server 2008
– Windows Server 2003
– Red Hat Enterprise Linux (RHEL) 5
To configure the pvSCSI adapter to be used by your disk, you'll have to follow this procedure:
01.) Launch a vSphere Client and log in to an ESX host system and select a virtual machine, or create a new one.
02.) Make sure that the OS is supported
03.) In the vSphere Client, right-click on the virtual machine and click Edit Settings.
04.) Click the Hardware tab > Add > select Hard Disk > Click Next
05.) Choose any one of the available options and click next
06.) Specify the options your require. Options vary depending on which type of disk you chose.
07.) Choose a Virtual Device Node between SCSI (1:0) to SCSI (3:15) and specify whether you want to use Independent mode, and click Next.
08.) Click Finish to finish the process and exit the Add Hardware wizard. A new disk and controller are created.
09.) Select the newly created controller and click Change Type.
10.) Click VMware Paravirtual and click OK. Then Exit and power On the VM.
11.) Install VMware Tools. VMware Tools includes the PVSCSI driver.
12.) Scan and format the hard disk.
UPDATE: The boot disks are supported with vSphere 4 – Update 1 now – See how-to do the changement here. Apparently booting from a disk attached to a PVSCSI adapter is not supported. The system software must be installed on a disk attached to an adapter that does support bootable disk.
Source: VMware