Some interesting links:
BizTalk Server Database Optimization White Paper – This is an excellent MSDN write-up on how to optimize your BizTalk systems. The title is somewhat incorrect as it describes how to optimize the hardware (which RAID level to use, turn off hyperthreading), the Network (usage of subnets), the OS (Registry and other settings) , IIS and SQL Server tuning. This is an extensive and through document that includes lab performance tests and results, recommended configurations and links to helpful tools and utilities.
Some of the suggestions can be helpful even if you aren’t using BizTalk.
Enterprise Service Bus (ESB) Guidance Documentation and Source Code – This is the CodePlex community site for the latest release (CTP3) of the ESB Guidance package for BizTalk. Current plan is to release the final version in October.