any good UPS for a Fedora server

John Summerfield debian at
Thu Nov 15 21:38:37 UTC 2007

Mikkel L. Ellertson wrote:
> 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.

If the mains is down, the power's off.

> 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?

Being away does not mean I don't want the computers running. I used them 
daily while away, it's how I knew one didn't come back up.

>> 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,

Without an autostart generator, the system would run for a 
strictly-limited, short time.

With one, it could run for days.

> 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.

Most power failures are a few seconds, sometimes some electrical 
appliances don't even seem to notice. Fairly recently, the clock on one 
oven kept running, the other didn't. Sometimes, some but not all 
unprotected computers restart.

Once one needs better protection than that, then one increases the time 
power may be on when it should not.

If it's a UPS protecting  a computer or two, it's only covering a small 
area, it doesn't matter so much, but when you go to backup power 
supplies powering a house or more (until the 60s we had no mains power, 
it was all 32-volt DC) then the likelihood increases quite a bit.



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