// Busy disk?

delta = 20 sec;		// force evaluation once every 20 seconds from here on

// If any disk is performing more than 60 I/Os per second, then
// print a message to standard output and launch dkvis(1)
//
some_inst
    disk.dev.total > 60 count/sec
	-> print "disk busy for 20 sec" "%v IOPS %i@%h" &
	   shell 5 min "dkvis";