New documentation was recently published which provides guidance and examples on how to configure your server farms for minimal downtime during software updates http://technet.microsoft.com/en-us/library/ee514459.aspx.
Actually, this is about mirrored environments or SQL clusters. It does not apply to all scenarios. ;-))
Correct, the document assumes a level of redundancy within the environment. While Microsoft SQL Server Database Mirroring is recommended in the article you can similarly acheive the same results/configuration under a failover cluster.
Thanks for commenting.