SQL Server 2008 R2 Clustering – How to Set Up Multiple Active Nodes

Note that all servers use the same NICs - Broadcom 5709Cs with up-to-date drivers. The servers themselves are Dell R610's.

Kyle Brandt has an opinion on Broadcom network cards which echoes my own (repeated) experience.

Broadcom, Die Mutha

My problems have always been associated with TCP Offload features and in 99% of cases disabling or switching to a-n-other network card has resolved the symptoms. One client that (as in your case) uses Dell servers, always orders separate Intel NICs and disables the on-board Broadcom cards on build.

As described in this MSDN blog post, I would start with disabling in the OS with:

netsh int ip set chimney DISABLED

IIRC it may be necessary to disable the features at the card driver level in some circumstances, it certainly won't hurt to do so.

I've found the answer to this problem. It is possible, but you either need Windows 2008R2 SP1 or higher, or a hotfix. The full details are at:

AlwaysOn Architecture Guide: Building a High Availability and Disaster Recovery Solution by Using Failover Cluster Instances and Availability Groups

To quote a line from this article: This arrangement of storage, where a cluster disk is shared between a subset of nodes within a WSFC, is referred to as asymmetric storage