Veritas InfoScale 7.3.1 Release Notes - Windows

Storage reclamation commands do not work when SFW is run inside Hyper-V virtual machines

This issue is observed on Hyper-V virtual machines where disks that support thin provisioning and reclamation are presented in a pass-through mode. SFW storage reclamation commands run inside a virtual machine appear to succeed, but the provisioned size of the LUNs remains unchanged. Hyper-V filters certain SCSI commands sent from the guest operating systems to the pass-through disks. Refer to the Microsoft Hyper-V documentation here:

http://technet.microsoft.com/en-us/library/dd183729(WS.10).aspx

This issue occurs because SFW uses one of the filtered SCSI commands to request thin storage reclamation. (2611988)

Workaround: In Windows Server operating systems, Hyper-V allows disabling the filtering of SCSI commands. This allows the full SCSI command set to be sent to the pass-through disks mapped to the virtual machine.

To disable SCSI command filtering, modify the virtual machine configuration and set the AllowFullSCSICommandSet property to True. Use the Virtualization WMI provider or edit the virtual machine configuration xml file manually. Refer to the Microsoft Hyper-V documentation for more details.

Alternatively, you can also use the following PowerShell script to disable SCSI command filtering for a virtual machine:

$HyperVGuest = $args[0]

$VMManagementService = gwmi Msvm_VirtualSystemManagementService 
-namespace "root\virtualization"

foreach ($Vm in gwmi Msvm_ComputerSystem 
-namespace "root\virtualization" -Filter "elementName='$HyperVGuest'")

{
$SettingData = gwmi -Namespace "root\virtualization" 
-Query "Associators of {$Vm}
Where ResultClass=Msvm_VirtualSystemGlobalSettingData 
AssocClass=Msvm_ElementSettingData"
$SettingData.AllowFullSCSICommandSet = $true
$VMManagementService.ModifyVirtualSystem
($Vm,$SettingData.PSBase.GetText(1)) | out-null
}

Save this script to a file and run it from the PowerShell command line on the Windows Server Hyper-V host system. The name of the virtual machine must be passed as an argument.

For example, if you save this script to a file named disablescsifiltering.ps1, run this script from the PowerShell command prompt as follows:

C:\>.\disablescsifiltering.ps1 virtualmachine_name

This script sets the AllowFullSCSICommandSet property value to True.