[rescue] adding power redundancy to single power supply systems ?

Ethan O'Toole ethan at 757tech.net
Mon Mar 24 18:52:36 CDT 2008

> How do you keep the equipment from failing when it switches from one output to the other?
> It would be quick, but would it be quick enough? If you put a UPS between the switch and the system it would work great...

I assume there is a cap of some sort in there... I mean, the place where I 
saw them used, they probably had a megawatt generator on the roof, and 
they were feeding PDU set A into one side, and PDU set B into the other 
side or something. So they could shift the PDUs. The UPS power was feeding 
INTO the switch, not the switch feeding the UPS.

I know personally it's a mixed bag. I have some PCs that will reboot on a 
sag, where others won't.

Since it's APC I assume there is something in there that covers it during 
the switch. I don't know what happens if you have power coming in at 
different phases... I assume it sends the glitch thru.

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