How is the cluster set up? Here is a common clustered setup I have seen:
- 2 node SQL Server cluster, clustered SSO master secret
- 2 node BizTalk cluster, SSO is installed (not master secret, and not clustered)
The important thing is to cluster the SSO master secret on the SQL cluster (or some other servers), not BizTalk. Here is the best install guide I have found:
http://www.microsoft.com/downloads/details.aspx?FamilyID=b273269c-97e0-411d-8849-5a8070698e4a&displaylang=en
It is titled “Installing and Configuring BizTalk Server in a Multi-Computer Environment”.