Linux Shell Scripting Cookbook - Third Edition

Gathering system I/O usage with dstat

Knowing what services are running may not tell you which services are slowing down your system. The top command (discussed in Chapter 9, Put on the Monitor's Cap) will tell you about CPU usage and how much time is spent waiting for IO, but it might not tell you enough to track down a task that's overloading the system.

Tracking I/O and context switches can help trace a problem to its source.

The dstat utility can point you to a potential bottleneck.