Enabling Virtual Machine Chimney on the Management Operating System

Applies To: Windows Server 2008 R2

Using Virtual Machine Chimney requires the presence of registry entries and values on the management operating system for network adapters to support TCP Chimney Offload.

There are two registry entries to add. One can enable or disable Virtual Machine Chimney on all 10 Gbps physical network adapters. The other can enable or disable Virtual Machine Chimney on all physical network adapters less than 10 Gbps. If the management operating system computer has a mix of network adapters—for example, both a 1 Gbps network adapter and a 10 Gbps network adapter—and both are capable of TCP Chimney Offload, you can add both entries and values.

Warning

Incorrectly editing the registry might severely damage your system. Before making changes to the registry, you should back up any valued data on the computer.

Registry entries for Virtual Machine Chimney

Registry entry Purpose Type Values

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\VMSMP\Parameters\
TenGigVmChimneyEnabled

Enable or disable Virtual Machine Chimney on all 10 Gbps physical network adapters

REG_DWORD

0=System default (disabled for Windows Server 2008 R2)
1=Enabled
2=Explicitly disabled

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\VMSMP\Parameters\
BelowTenGigVmChimneyEnabled

Enable or disable Virtual Machine Chimney on all physical network adapters less than 10 Gbps

REG_DWORD

0=System default (disabled for Windows Server 2008 R2)
1=Enabled
2=Explicitly disabled

To enable Virtual Machine Chimney on a management operating system with physical network adapters less than 10 Gbps

  1. To open an elevated Command Prompt window, click Start, point to All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.

  2. Type reg add HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\VMSMP\Parameters\BelowTenGigVmChimneyEnabled /t REG_DWORD /d 1 /f, and then press ENTER.

To enable Virtual Machine Chimney on a management operating system with 10 Gbps physical network adapters

  1. To open an elevated Command Prompt window, click Start, point to All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.

  2. Type reg add HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\VMSMP\Parameters\TenGigVmChimneyEnabled /t REG_DWORD /d 1 /f, and then press ENTER.