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Changing Paravirtualized SCSI Controller Queue Depth in VMware ESXi 4.x/5.0 (1017423)

Purpose

This article provides steps to change the disk queue depth for a Paravirtualized SCSI adapter on Windows.

You may need to increase the disk queue depth for a Paravirtualized SCSI adapter to improve performance due to heavy disk workload.

Resolution

To change the disk queue depth for a Paravirtualized SCSI adapter:

Note: This procedure modifies the Windows registry. Before making any registry modifications, ensure that you have a current and valid backup of the registry and the virtual machine. For more information on backing up and restoring the registry, see the Microsoft article 136393.

  1. Click Start > Run, type regedit, and press Enter. The Registry Editor window opens.
  2. Navigate to this path:

    [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\pvscsi\Parameters\Device]

    Note: If the end of the path does not exist, create the last keys.

  3. In the Device key, create or modify a string value named DriverParameter.
  4. Set the value data of the DriverParameter to:

    "MaxQueueDepth=128"

    Note: Do not remove the quotation marks.

  5. Reboot the guest operating system.

Additional Information

ESX LUN Queue Depth (which by default is 30 on Emulex and 32 on QLogic) must be changed if you want to go beyond 64 with the PVSCSI driver. For more information, see Changing the queue depth for QLogic and Emulex HBAs (1267).

Note: In some scenarios you may need to make changes on the storage as it has similar limitations on I/O per LUN at a time.



Note: The links in this article were correct as of January 7, 2013. If you find a link is broken, provide feedback and a VMware employee will update the link.

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