Paravirtualized SCSI (PVSCSI) is a high-performance storage
adapter available in VMware vSphere 4. The PVSCSI adapter is best-suited for
virtual machines that run applications which generate heavy I/O.
The vSphere 4 performance study compares the performance of
PVSCSI with LSI Logic for Fibre Channel and software iSCSI protocols. The
experiments show that PVSCSI greatly improves CPU efficiency and improves
throughput when the workload drives very high I/O rates. For Fibre Channel, the
test results show that PVSCSI
reduces the CPIO by 10%-30%. For iSCSI, PVSCSI reduces the CPIO
by up to 25%.
To read the full study, go to http://www.vmware.com/pdf/vsp_4_pvscsi_perf.pdf.
To learn how to configure disks to use the PVSCSI adapter, see http://kb.vmware.com/kb/1010398.
For one workload exception where LSI Logic is better, see http://kb.vmware.com/kb/1017652.