dstat
Homepage description:
Dstat is a versatile replacement for vmstat, iostat, netstat and ifstat. Dstat overcomes some of their limitations and adds some extra features, more counters and flexibility. Dstat is handy for monitoring systems during performance tuning tests, benchmarks or troubleshooting.
Dstat allows you to view all of your system resources in real-time, you can eg. compare disk utilization in combination with interrupts from your IDE controller, or compare the network bandwidth numbers directly with the disk throughput (in the same interval).
Dstat gives you detailed selective information in columns and clearly indicates in what magnitude and unit the output is displayed. Less confusion, less mistakes.