The next time a salesman tells you that a server needs redundant powersupplies for reliability, ask him if the server also has redundant CPUfans.

By now, most everyone understands that extended warranties on consumerelectronics are just overpriced insurance (hence why the salescrittertries to get you to buy them, as they're great profit for the store).Redundant power supplies are getting to be a standard option in serverconfigurations, and while they're not necessarily pointless I have tofeel that a fair number of people

If you don't have the time to say hi to a passing cat, you need toslow down.

If you never have time to say hi to passing cats, you definitely need to slow down.

(Aphorism void where prohibited by allergies. Applications to thetypical sysadmin lifestyle are left as an exercise for the readers.)

Back in June, I wrote about how unchanging systems should be stable . There isan important consequence of this:

To control stability, you must control change.

(This clearly follows from change being the only thing can destabilizeyour unchanging stable systems.)

I think that this is subtly different from taking changes carefullybecause the changes themselves could possibly be broken. This is therealization that any change may perturb the overall system, requiringit to be restabilized; it is the need to control what one has definedas the