At 09:26 PM 8/8/97 -0700, Tony Li wrote:
That takes us back to UPSi on equipment, and generators. Technologies available are: ....
Don't forget cogeneration equipment.
One would think that local power, UPS, and one flavor of generator should suffice. For the "reasonable". ;-)
Having built a large datacenter recently (PointCast's), I can say that we planned for local power failures that lasted up to about 48 hours. If it's worse than that, you have A Big Problem. We made our system completely automatic since it might have to operate when there was no operator to initiate a transfer (although for the first year we didn't have this). One thing to watch out for is the problem of utility power "coming back" and then dying again. This caused at least one ISP accident since they had insufficient battery power to transfer from Utility->Battery->Generator and back to Utility and then do it again. This is especially a problem if you manually initiate your generators (which is by far the most common situation). These kinds of multiple transfers are actually more common than you think. -jcp-
Tony
-- Joseph C. Pistritto jcp@jcphome.com Belmont, California http://www.wp.com/jcp