Performance Monitoring: Correlations

Although I have been arguing that performance monitoring and capacity planning require a decent server montoring environment, it also requires more. This extra part comes from the fact that often services depend on each other. A web service connects to a database (hosted on a different server) and fetches data from the file server (local, or SAN/NAS). Often, one part in the chain is a bottleneck for the whole of the process. This is a shame and can be avoided by careful analysis of the correlations between performance data.

Again, this is an argument in favor of what I called a 'load profile' earlier. By modeling a server by means of a load profile, we get a representation of that server in terms of measurable quantities. Statistics and mathematics in general can then help us analyze the correlations between those load profiles.