I'd like to watch disk activity on my USB external hard drive. I know that I can use
iotop to monitor disk I/O for each running process, but is there a way to get a measure per filesystem?
dstat is better than iostat for strictly monitoring disk activity.
I am running the following command while moving files from one harddrive to another
dstat -D sda,sdc
for more info, have a look at this page
I'm not skilled in this area, but iostat comes to mind. You can install it with the sysstat package. Good luck!
iostat from the
sysstat package provides a single snapshot of results since startup. Use of the interval parameter will append the results for only the last interval to the output. Example,
iostat 10 will first show the "since boot" values then continue to add the last 10 seconds of statistics to the output, every 10 seconds. Include the
-y option to omit the first display of statistics since boot but understand that the command will appear idle for the specified interval while the system collects the first snapshot.
I've found this most effective when combined with the
watch command and indicating to only collect for a single interval of statistics. For example:
watch -t -n 0.1 iostat -p sda,sdc -d -t -y 5 1
This gives a refresh every 5.1 seconds of activity statistics for the last 5 seconds. To break down the options and parameters...
- The first
watchto omit the header. This is to avoid confusion that otherwise the header will include "Every 0.1s" which does not represent the snapshot of data.
watchto run the following command every 0.1 seconds. This is the smallest interval for
procps-ng 3.3.9) but don't worry, it isn't actually running the command every 0.1 seconds. It will run the command 0.1 seconds after the prior instance completes.
iostatto only display stats for these devices.
iostatto only display device utilization, relevant since the question was concerning disk activity.
- The second
iostatto include the time of the refresh in the statistics. This is useful since the earlier omission of the
watchheader removed the time display that would have been there.
-yswitch omits the first screen of "since boot" statistics from the interval display. Without this the result would be a display of the statistics since boot updating at the interval of the watch command.
5 1are the
iostatinterval parameters. In this case capture 5 seconds of statistics once (the 1). Because the
-yswitch was used this will only present a single screen of data.
It will take 5 seconds for
iostat to collect the data, it will then be displayed in
watch, and 0.1 seconds later watch will trigger the
iostat command again. 5 seconds later the new data will replace the old,
watch will wait 0.1 seconds, wash, rinse, repeat...
In order to monitor disk IO per device and process in one glance, consider using
You can install it with
pip install glances