Database Mirroring Performance Monitoring
Many people deploy performance monitoring solutions in a "one-size-fits-all" manner. That is, they tend to build a solution that can be easily deployed to multiple servers and capture basic information from each server. The trouble is that not every server is identical, not even within the same shop. For example, not every server may have database mirroring deployed, which means your performance monitoring solution may be missing some critical pieces of information with regards to monitoring database mirroring.