True. Note also that Perfkit has a set of default thresholds for this sort of thing prebuilt; it may be cheaper to activate it rather then writing your own.
It really wouldn't be too complicated to have a disconnected service machine that puts out a message every five minutes (plus or minus whatever desired) and sends a line or two to the system operator indicating things such as CPU Utilization, Paging Rate, I/O, and Spool and Page Utilization. This way, it's logged how the system is performing in case a user calls with a performance issue (complaint) - and also help keep track of the system to prevent a catastrophic situation.
