Linux System monitoring using Dstat

dstat  is a versatile replacement for vmstat, iostat, netstat, nfsstat, and ifstat. It includes various counters (in separate plugins) and allows you to select and view all of your system resources instantly; you can, for example, compare disk usage in combination with interrupts from your IDE controller, or compare the network bandwidth numbers directly with the disk throughput (in the same interval).

Dstat also cleverly gives you the most detailed information in columns and clearly indicates in what magnitude and unit the output is displayed. Less confusion, less mistakes, more efficient.

Dstat is unique in letting you aggregate block device throughput for a certain diskset or network bandwidth for a group of interfaces, ie. you can see the throughput for all the block devices that make up a single filesystem or storage system.

Dstat allows its data to be directly written to a CSV file to be imported and used by OpenOffice, Gnumeric or Excel to create graphs.

Download:
OpenSuse 11: here
Fedora: here

After downloading the rpm file, install it using command: rpm -ivh dstat-0.6.8-3.1.noarch.rpm

Using Dstat
Using dstat to relate disk-throughput with network-usage (eth0), total CPU-usage and system counters:

dstat -dnyc -N eth0 -C total -f 5

Checking dstat's behaviour and the system's impact on dstat:

dstat -taf --debug

Using the time plugin together with cpu, net, disk, system, load, proc and topcpu plugins:

dstat -tcndylp -M topcpu

this is identical to: dstat -M time,cpu,net,disk,sys,load,proc,topcpu

Using dstat to relate cpu stats with interrupts per device:

dstat -tcyif

Get a Report by Mail
There may be cases wherein you want to observe how your server is performing over a period of time. You can setup a background process in Linux that will give you a reading with a certain interval, generate a report, and mail out the file to you.

The following script will run Dstat for three hours, reading the data every 30 seconds, and will mail out the report to me@myemailid.com.

    #!/bin/bash
    dstat –output /tmp/dstat_data_mail.csv -CDN 30 360
    mutt -a /tmp/dstat_data_mail.csv -s “Dstat Report for 3 hour run” me@myemailid.com <  /dev/null

Save the above script in a file called dstat_script.sh on your server, give it executable permission and then run it as a background process:

# chmod +x dstat_script.sh
# nohup ./dstat_script.sh &

Done. Yes, it’s that simple. You will now be mailed this report after it’s done running. You can optionally schedule this script as a daily cron job so that you can receive this data every day.