212 IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning
When you are capturing data to a file, the nmon tool disconnects from the shell to ensure that it
continues running even if you log out. This means that nmon can appear to crash, but it is still
running in the background until the end of the analysis period.
7.4.3 filemon
The filemon command monitors a trace of file system and I/O system events, and reports
performance statistics for files, virtual memory segments, logical volumes, and physical
volumes. The filemon command is useful to those whose applications are believed to be
disk-bound, and want to know where and why.
The filemon command provides a quick test to determine if there is an I/O problem by
measuring the I/O ...