Incorrect output from mmpmon

If the output from mmpmon is incorrect, such as zero counters when you know that I/O activity is taking place, consider these points:

1. Someone may have issued the reset or rhist reset requests.
2. Counters may have wrapped due to a large amount of I/O activity, or running mmpmon for an extended period of time. For a discussion of counter sizes and counter wrapping, see Counter sizes and counter wrapping section in Monitoring I/O performance with the mmpmon command.
3. See the Other information about mmpmon output section in Monitoring I/O performance with the mmpmon command. This section gives specific instances where mmpmon output may be different than what was expected.