Configuration of Paravirtual SCSI (PVSCSI) Adapters

SUMMARY

Configuration of Paravirtual SCSI (PVSCSI) Adapters

ISSUE

Purpose

As we are beginning to notice that some of our customers are choosing to use paravirtual controllers more often, this document explains what paravirtual controllers are, how they can be used, and how to configure them.

Description

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. VMware recommends that you create a primary adapter (LSI Logic by default) for use with a disk that will host the system software (boot disk) and a separate PVSCSI adapter for the disk that will store user data, such as a database. 
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:

  • Boot disks 
  • Record/Replay
  • Fault Tolerance
  • MSCS Clustering 

 

This table shows the support matrix for use of Paravirtual SCSI adapters for data disks and boot disks for the various guest operating systems and ESX versions. Support shown in the table is from the listed ESX/ESXi version and later versions. 

 

Guest operating system

Data Disk

Boot Disk

Windows Server 2008 R2 (64-bit only)

ESX/ESXi 4.0 Update 1, ESX/ESXi 4.1, ESXi 5.0

ESX/ESXi 4.0 Update 1, ESX/ESXi 4.1, ESXi 5.0

Windows Server 2008 (32 and 64 bit)

ESX/ESXi 4.X, ESXi 5.0

ESX/ESXi 4.0 Update 1, ESX/ESXi 4.1, ESXi 5.0

Windows Server 2003 (32 and 64 bit)

ESX/ESXi 4.x, ESXi 5.0

ESX/ESXi 4.x, ESXi 5.0

Windows 7 (32 and 64 bit)

ESX/ESXi 4.1, ESXi 5.0

ESX/ESXi 4.1, ESXi 5.0

Windows Vista (32 and 64 bit)

ESX/ESXi 4.1, ESXi 5.0

ESX/ESXi 4.1, ESXi 5.0

Windows XP (32 and 64 bit)

ESX/ESXi 4.1, ESXi 5.0

ESX/ESXi 4.1, ESXi 5.0

Red Hat Enterprise Linux (RHEL) 5 (32 and 64 bit) and all update releases

ESX/ESXi 4.X, ESXi 5.0

Not Supported

RHEL 6 (32 and 64 bit)

ESX/ESXi 4.0 Update 2, ESX/ESXi 4.1, ESXi 5.0

ESX/ESXi 4.0 Update 2, ESX/ESXi 4.1, ESXi 5.0

SUSE Linux Enterprise 11 SP1(32 and 64 bit) and later releases

ESX/ESXi 4.0 Update 2, ESX/ESXi 4.1, ESXi 5.0

ESX/ESXi 4.0 Update 2, ESX/ESXi 4.1, ESXi 5.0

Ubuntu 10.04 (32 and 64 bit) and later releases

ESX/ESXi 4.0 Update 2, ESX/ESXi 4.1, ESXi 5.0

ESX/ESXi 4.0 Update 2, ESX/ESXi 4.1, ESXi 5.0

Distros using Linux version 2.6.33 or later and that include the vmw_pvscsi driver

ESX/ESXi 4.1, ESXi 5.0

ESX/ESXi 4.1, ESXi 5.0

 
     

 

Because the default type of newly hot-added SCSI adapter depends on the type of primary (boot) SCSI controller, hot-adding a PVSCSI adapter is only supported for those versions that support booting from a PVSCSI adapter.

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.

Cause

 

Resolution

To configure a disk to use a PVSCSI adapter:

  1. Launch a vSphere Client and log in to an ESX/ESXi host or vCenter Server.
  2. Select a virtual machine, or create a new one.
  3. Ensure a guest operating system that supports PVSCSI is installed on the virtual machine.
  4. In the vSphere Client, right-click on the virtual machine and click Edit Settings.
  5. Click the Hardware tab.
  6. Click Add.
  7. Select Hard Disk.
  8. Click Next.
  9. Choose any one of the available options.
  10. Click Next
  11. Specify the options your require. Options vary depending on which type of disk you chose.
  12. Choose a Virtual Device Node and specify whether you want to use Independent mode. For data disks choose a Virtual Device Node between SCSI (1:0) to SCSI (3:15). For a boot disk choose Virtual Device Node SCSI (0:0), or choose the Virtual Device Node that will boot in the order you require.
  13. Click Next.
  14. Click Finish to finish the process and exit the Add Hardware wizard. A new disk and controller are created.
  15. Select the newly created controller and click Change Type.
  16. Click VMware Paravirtual and click OK.
  17. Click OK to exit the Virtual Machine Properties dialog.
  18. Power on the virtual machine.
  19. Install VMware Tools. VMware Tools includes the PVSCSI driver.
  20. Scan and format the hard disk.

Note: In some operating systems, you need to create a virtual machine with the LSI controller, install VMware Tools, then change to the drives to paravirtualized mode to perform the procedure above.

 

Third-Party Sources

 

 

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