For a long time, I was not satisfied with vmstat, because it does not generate timestamps. Then I came across a cool program named Dstat yesterday, which can be an excellent replacement for vmstat.

A screenshot of Dstat

By using Dstat, now not only all my needs can be met but also it is pretty easy to do resource usage analysis and graphing.

As the author described, “Dstat is a versatile replacement for vmstat, iostat, netstat, nfsstat 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.” So why use three or more tools when one tool can give you everything you need?

Here is an example showing how to use it.

First, capture the resource usage information (CPU and memory) to a file, e.g. stat.dat:

$ dstat -tcmn > stat.dat

Then use the scripts below to create CPU and memory usage graphs:

#!/usr/bin/gnuplot
 
set terminal png
set output "cpu.png"
set title "CPU usage"
set xlabel "time"
set ylabel "percent"
set xdata time
set timefmt "%d-%m %H:%M:%S"
set format x "%H:%M"
plot "stat.dat" using 1:4 title "system" with lines, \
"stat.dat" using 1:3 title "user" with lines, \
"stat.dat" using 1:5 title "idle" with lines

#!/usr/bin/gnuplot
 
set terminal png
set output "memory.png"
set title "memory usage"
set xlabel "time"
set ylabel "size(M Bytes)"
set xdata time
set timefmt "%d-%m %H:%M:%S"
set format x "%H:%M"
plot "stat.dat" using 1:9 title "used" with lines, \
"stat.dat" using 1:10 title "buff" with lines, \
"stat.dat" using 1:11 title "cach" with lines, \
"stat.dat" using 1:12 title "free" with lines

Resource usage graph examples:

Download the scripts.
http://www.zhuzhaoyuan.com/download/dstat/cpu.sh
http://www.zhuzhaoyuan.com/download/dstat/memory.sh