This is a plugin that shows the file and directory activity on the array by disk.  This includes read and write activity on the array.  Read activity can cause disk spin ups.  It is recommended that you have the Dynamix Cache Directories plugin installed and running.   The plugin uses inotify to log read and write disk activity.  You will need to start File Activity to start the logging.  I don't recommend leaving it on all the time.  A server with a lot of file activity can fill the l