Yup. Related: "100% availability" is a marketing person's dream; it sounds good in theory but is unattainable in practice, and is a reliable sign of non-100%-reliability.
You are confusing two different things.
No, I'm not. They're interrelated. That doesn't mean that they are the same thing, but to talk about them in terms of their relationship or their effect on service is perfectly fair.
And even for those who follow best practices... You can inspect and maintain things until you're blue in the face. One day a contractor will drop a wrench into a PDU or UPS or whatever and spectacular things will happen.
That's were policies, procedures and methods come in (read: SAS70)
Policies, procedures, and methods are nice. Unfortunately, it is not too uncommon for all of the above to be bent or broken for a whole slew of reasons. What about a problem that hasn't been planned for? It only takes one time ... one mistake ... of just the right kind.
Or a battery develops a strange fault.
Get more than one string, one more than one UPS, with monitoring. Batteries are NOT the Achilles heel everyone wants to make you believe they are.
I know you have a rather higher faith in batteries than some of us, but practical experience suggests that batteries are merely a mostly- reliable technology. ... JG -- Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net "We call it the 'one bite at the apple' rule. Give me one chance [and] then I won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN) With 24 million small businesses in the US alone, that's way too many apples.