To find disk I/O latency with the ioping monitoring tool on Linux, you will need to install ioping first. You can do this using your system's package manager. For example, on a Debian-based system, you can run the following command:
sudo apt-get install ioping
Once ioping is installed, you can use it to measure the I/O latency of a disk or partition by specifying the path to the disk or partition as an argument. For example, to measure the I/O latency of the /dev/sda1 partition, you can run the following command:
sudo ioping /dev/sda1
This will start ioping in latency measurement mode and display the I/O latency of the specified partition in real-time. The output will look something like this:
4.0 kB/s | 17.6 ms | 17.6 ms | 17.6 ms
The first column shows the throughput (in kB/s), and the second column shows the I/O latency in milliseconds. The third column shows the average latency over the last 10 requests, and the fourth column shows the average latency over the entire measurement period.
You can use the -c option to specify the number of requests to send before exiting. For example, to send 100 requests and then exit, you can run the following command:
sudo ioping -c 100 /dev/sda1
You can also use the -D option to measure the disk seek latency instead of the I/O latency.
For more information about ioping and its options, you can refer to the man page by running man ioping in a terminal.