September 24, 2008

1. Longitude Report showing CPU spike - Click to enlarge

2. Longitude Report showing CPU spike with annotations - Click to enlarge

Every now and then, our Tech Support line receives a question from a customer or prospect about how to deal with spikes in resource usage and the corresponding performance bottlenecks. Typically, they have either generated a graph showing a spike visually (with CPU usage being a common culprit), or they have noticed an event or received an email alert about a sudden bottleneck. They need to find out what caused the spike and how to respond.

Whenever you see a sudden change like the one shown (Figure 1), first think about what day and time of day the spike occurred and whether it may have been an expected activity. Are there regular production processes that are resource intensive, such as month-end processing that might be done overnight at the beginning of the following month? Does the spike correspond to a planned maintenance window on the system in question? What about periodic virus updates, patch applications, reboots, or backup processes? If the answer to any of these questions is “yes,” then the quickest way to identify the problem may be to pick up the phone and verify the situation with a colleague.