A number of customers have been enquiring about the current situation of our Scalable Networking Pack in relation to Windows 2008 and thanks to Jane Lewis of the UK PFE team for running the ground work on this. So, Info and recommendations are as follows;
With Windows 2003 SP2 this setting was enabled by default. Many customers experienced issues post deployment and http://support.microsoft.com/kb/948496/jp. This was related to the fact that certain NIC cards especially Broadcom had some major compatibility issues. Network cards using Broadcom 5708 chipsets are known to have compatibility issues with the TCP Chimney Offload feature set and many a blog has been written around these issues;
http://blogs.msdn.com/sqlprogrammability/archive/2008/05/27/sql-server-intermittent-connectivity-issue.aspx & http://blogs.technet.com/networking/archive/2008/11/14/the-effect-of-tcp-chimney-offload-on-viewing-network-traffic.aspx and http://support.microsoft.com/kb/942861
It was therefore advisable to “Switch off” the SNP via this registry key.
EnableTCPA REG_DWORD 0x0 ßOK
EnableRSS REG_DWORD 0x0 ßOK
EnableTCPChimney REG_DWORD 0x0 ßOK
0 = disabled
1 = enabled default
With the release of 2008 I have been asked by many of my customers whether this remains an issue.
Well the answer is that IT COULD WELL BE!, however to mitigate the issue ensure that you have the LATEST NIC card drivers included as part of your server build, and checkout their comptibility with TCP Chimney Offload feature with the NIC Vendors
Windows 2008 specific reference to Scalable Networking Pack.
As always - feedback welcome from the field