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03. [10p] Iotop
[5p] TASK A - Good to know
Iotop is an utility similar to top command, that interfaces with the kernel to provide per-thread/process I/O usage statistics.
Debian/Ubuntu Linux install iotop $ sudo apt-get install iotop How to use iotop command $ sudo iotop OR $ iotop
Supported options by iotop command:
| Options | Description | |
| –version | show program’s version number and exit | |
| -h, –help | show this help message and exit | |
| -o, –only | only show processes or threads actually doing I/O | |
| -b, –batch | non-interactive mode | |
| -n NUM, –iter=NUM | number of iterations before ending [infinite] | |
| -d SEC, –delay=SEC | delay between iterations [1 second] | |
| -p PID, –pid=PID | processes/threads to monitor [all] | |
| -u USER, –user=USER | users to monitor [all] | |
| -P, –processes | only show processes, not all threads | |
| -a, –accumulated | show accumulated I/O instead of bandwidth | |
| -k, –kilobytes | use kilobytes instead of a human friendly unit | |
| -t, –time | add a timestamp on each line (implies –batch) | |
| -q, –quiet | suppress some lines of header (implies –batch) | |
[5p] TASK B - Monitoring the behaviour
Datafile: dummy.sh.
- Run iotop (install it if you do not already have it) in a separate shell showing only processes or threads actually doing I/O.
- Inspect the script code (dummy.sh) to see what it does.
- Monitor the behaviour of the system with iotop while running the script.
- Identify the PID and PPID of the process running the dummy script and kill the process using command line from another shell (sending SIGINT signal to both parent & child processes).
If apt-get install returns an error (something along the lines of failed to update ramfs) note that iotop was probably still installed for the current session. Try running it before stating that it doesn't work!
