Re: any good UPS for a Fedora server

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John Summerfield wrote:
> Mikkel L. Ellertson wrote:
>> John Summerfield wrote:
>>> In the event of a quake, it seems to me prudent to cut HT and mains, but
>>> then generator sets automatically starting up would tend to negate the
>>> action.
>>>
>> Not really - before you cut the mains, you switch the generator set
>> control to off instead of auto. 
> 
> And if the power goes when nobody's home?
> 
The same thing as happens if the power does not go out. Unless your
generator runs out of fuel before the power comes back on. After
all, if nobody is home, you are not going to cut the mains either.
On the other hand, if you do not want the generator to run while you
are gone, then turn the selector to off as part of the normal
preparation for being gone for 2 weeks. You do do things like turn
off the water heater, put the thermostat in the away setting, and
things of that nature, right?
> 
> I was away two weeks recently, and the power went while I was away. One
> of the systems didn't come up, and when I got back a week later the
> office had an evil smell, the smoke got out of a switch.
> 
About the only change having an auto-start generator would be that
your power would have been out for a shorter period of time,
anything on a UPS would not have stopped running, the UPS batteries
would not have gotten depleted, and maybe the smoke would not have
come out of the switch. (Unless the delay before the generator
started was longer then the UPS run time.) Most transfer switches
are like most UPSs - line power has to be restored, stable, and
within the proper range for a period of time before the switch to
line power is made. This has an added benefit of protecting your
equipment from line fluctuations that are common when power is first
restored.

I fail to see how a properly installed auto-start generator would
increase your risk. The transfer switch isolates the generator from
the outside power - there is never a connection between the
generator and outside power. The only place they should meet is in
the transfer switch, and that is configured so that only one can be
connected to the load at a time, and the two sources can never be
connected to each other. I can see how an improperly connected
generator can cause problems, but that is a problem in any case.

Mikkel
-- 

  Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!

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