nanog mailing list archives
Re: "They all suck!" Re: UPS failure modes (was: fire at NAC)
From: Alex Rubenstein <alex () nac net>
Date: Thu, 29 May 2003 16:39:56 -0400 (Eastern Daylight Time)
UPSes (and UPS batteries) do fail, sometimes in catastrophic ways. I would not design any critical system on the assumption that any particular component won't fail. High availability is about designing for failure. Sometimes there is a long time between failures, other times they occur early and often. The most annoying thing about UPSes is they fail at exactly the time they are needed most.
Except, that: Even in instances where 'High availability' is designed, in the case where one of the units has a failure that causes a fire and FM200 dump, either the FM200 will still trigger an EPO, or the fire department will. So, the second 'high available' unit will generally not prevent you from dropping the critical load, but instead, will help you get back on line quicker. A much cheaper and easier to implement external maintenance make-before-break bypass will accomplish the same thing. I've heard many a story of the paralleling gear causing the problem in the first place, as well... -- Alex Rubenstein, AR97, K2AHR, alex () nac net, latency, Al Reuben -- -- Net Access Corporation, 800-NET-ME-36, http://www.nac.net --
Current thread:
- Re: UPS failure modes (was: fire at NAC), (continued)
- Re: UPS failure modes (was: fire at NAC) Simon Lockhart (May 29)
- Re: UPS failure modes (was: fire at NAC) Alex Rubenstein (May 29)
- Re: UPS failure modes (was: fire at NAC) Timothy Brown (May 29)
- Re: UPS failure modes (was: fire at NAC) Pete Ehlke (May 29)
- Re: UPS failure modes (was: fire at NAC) Joel Jaeggli (May 29)
- Re: UPS failure modes (was: fire at NAC) Arman (May 29)
- Re: UPS failure modes (was: fire at NAC) nicholas harteau (May 29)
- Re: UPS failure modes Jack Bates (May 29)
- Re: "They all suck!" Re: UPS failure modes (was: fire at NAC) Alex Rubenstein (May 29)
- Re: "They all suck!" Re: UPS failure modes (was: fire at NAC) Dan Armstrong (May 29)
- Re: "They all suck!" Re: UPS failure modes (was: fire at NAC) Sean Donelan (May 29)
- Re: "They all suck!" Re: UPS failure modes (was: fire at NAC) Sean Donelan (May 29)
- Re: "They all suck!" Re: UPS failure modes (was: fire at NAC) E.B. Dreger (May 29)
- Message not available
- Re: "They all suck!" Re: UPS failure modes (was: fire at NAC) Kevin Day (May 29)
- Re: "They all suck!" Re: UPS failure modes Jack Bates (May 29)
- Re: "They all suck!" Re: UPS failure modes Dan Hollis (May 29)
- Re: "They all suck!" Re: UPS failure modes Stephen Sprunk (May 29)
- Re: "They all suck!" Re: UPS failure modes Dan Hollis (May 30)