Master Linux Performance Monitoring with iostat: Installation, Usage, and Advanced Tips

Installation

Most Linux distributions include iostat via the sysstat package; if it is missing, install it with the appropriate package manager.

sudo apt-get install sysstat

sudo yum install sysstat

Basic Usage

1 View overall disk and CPU statistics

Run iostat to display average CPU utilization and per‑disk I/O activity.

iostat

2 Specify interval and count

Use -t to set the reporting interval in seconds and -c to set the number of reports.

iostat -t 2 5

Understanding iostat output

The output contains several columns, including:

avg-cpu : average CPU usage statistics (user, system, idle).

Device : name of the disk device.

tps : transfers per second, i.e., number of I/O operations per second.

kB_read/s : kilobytes read per second.

kB_wrtn/s : kilobytes written per second.

%util : percentage of time the device was busy.

Example Commands

1 Monitor disk I/O

iostat -d -t 2 10

This displays disk I/O statistics every 2 seconds, for a total of 10 reports.

2 Monitor CPU utilization

iostat -c -t 2 10

This shows CPU utilization every 2 seconds, for 10 reports.

Advanced Usage

1 Monitor specific partition

iostat -p /dev/sda1 -t 2 10

Monitors the I/O of the /dev/sda1 partition every 2 seconds, 10 times.

2 Custom output format (CSV)

iostat -c -o CSV -t 2 10

Outputs CPU statistics in comma‑separated values.

3 Redirect output to a file

iostat -d -t 2 10 > iostat_output.txt

Saves the disk I/O statistics to iostat_output.txt for later analysis.

4 Monitor network devices

iostat -n -t 2 10

Shows network interface statistics every 2 seconds, 10 times.

5 Remote monitoring

iostat -d -t -h remote_host

Connects to remote_host and monitors its disk I/O.

6 Show block devices

iostat -k -t 2 10

Displays I/O statistics for block devices every 2 seconds, 10 times.

7 Select specific columns

iostat -x -t 2 10

Shows only the chosen columns (e.g., device, transfer rate, utilization) every 2 seconds, 10 times.

Conclusion

iostat is a powerful utility for tracking disk I/O and CPU performance, making it valuable for troubleshooting, performance tuning, and overall system health monitoring.