an example where he noticed a lot of I/O being generated on a particular LUN. How do you figure out who / what is causing this? Well it is not as difficult as you think it would be…

1. Open up esxtop (more details on my )

2. Go to the “Device” view (U)

3. Find the device which is causing a lot of I/O

4. Press “e” and enter the “Device ID” in my case that is an NAA identifier so “copy+paste” is easiest here

5. Now look up the World ID under the “path/world/partition” column

6. Go back to CPU and sort on %USED (press “U”)

7. Expand (press “e”) the world that is consuming a lot of CPU, as CPU is needed to drive I/O

This should enable you to figure out which world is driving the high amount of I/Os. Now you can kill it, contact the user / admin causing it… nice right.