"They all suck!" Re: UPS failure modes (was: fire at NAC)

Sean Donelan sean at donelan.com
Thu May 29 20:30:46 UTC 2003

On Thu, 29 May 2003, Robert Boyle wrote:
> The reason for this rambling post is to ask if others have had similar
> problems with other UPS brands. I think they should have enough fail-safes
> built-in that they are never the CAUSE of an outage much less a fire! Based
> on my experience and NAC's incident today, is that an unreasonable
> expectation? I don't think manufacturers specify MTBF (mean time before

A quote from the facility manager of a large ISP with multiple data
centers in Northern Virginia, each using a different brand of UPS and
backup systems (batteries, flywheels, generators, etc).
Q: Which UPS brand do you think is best?
A: They all suck!

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.

The FCC NRIC Focus Group 2 is now accepting "voluntary" outage reports
from Internet Service Providers.  See http://www.nric.org/ for details.

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