Paravirtual SCSI (PVSCSI) adapters are high-performance storage adapters that can result in greater throughput and lower CPU utilization. Paravirtual SCSI adapters are best suited for high performance storage environments. Paravirtual SCSI adapters are not suited for DAS environments.

Paravirtual SCSI adapters are available for virtual machines running hardware version 7 and greater. They are supported on the following guest operating systems:

Windows Server 2008

Windows Server 2003

Red Hat Linux (RHEL) 5

The following features are not supported with Paravirtual SCSI adapters:

on Linux

Record/Replay

Fault Tolerance

MSCS Clustering

Paravirtual SCSI adapters have the following limitations:

Hot-add and Hot-remove requires a bus rescan from within the guest.

(Windows guests) In the Computer Management console, right-click Storage > Disk Management and select Rescan Disks.

(Linux guests) See the Red Hat Linux Web site for the most current instructions.

Disks on Paravirtual SCSI adapters might not experience performance gains if they have snapshots or if memory on the ESX host is over committed.

If you upgrade from RHEL 5 to an unsupported kernel, you might not be able to access data on the disks attached to a Paravirtual SCSI adapter. To regain access to such disks, run the VMware Tools configuration (vmware-config-tools.pl) with kernel-version parameter and pass the kernel version after the kernel is upgraded and before the virtual machine is rebooted. Run uname -r to determine the version of the running kernel.