Monitoring disk activity

Going by the popular naming convention of monitoring tools ending in the word 'top' (the command used to monitor processes), the tool to monitor disk I/O is called iotop.

Getting ready

iotop doesn't come preinstalled with most Linux distributions, you will have to install it using your package manager.

How to do it...

There are multiple ways of using iotop to perform I/O monitoring, some of which we will see in this recipe:

1. For interactive monitoring, use:

   # iotop -o
   

   The -o option to iotop tells it to show only those processes which are doing active I/O while it is running. It is a useful option to reduce the noise in the output.

2. For non-interactive use from shell scripts, use:

   # iotop -b -n 2
   

   This will tell iotop to print the statistics two times and then exit, which is useful if we want this output in a shell script and do some manipulation on it.

3. Monitor a specific process using the following:

   # iotop -p PID
   

   Put PID of the process that you wish to monitor, and iotop...