nanog mailing list archives

Re: HE.net, Fremont-2 outage?


From: "Michael K. Smith" <mksmith () adhost com>
Date: Wed, 04 Nov 2009 11:21:37 -0700




On 11/4/09 11:44 AM, "Alex Rubenstein" <alex () corp nac net> wrote:

Regardless of generator sizing issues or disparities, if the ATS fails,
then no amount of grid or generator power will keep the cabinets juiced up.

That is patently false.

At it's root it's true - if an ATS fails the power between the source and
destination will be interrupted.
 
Assume N+1 UPS, with each UPS module having its own ATS fed from a utility and
emergency bus. Then you can even individually maintain each UPS module and
ATS. Bonus and score.

And if it's a really good place, you have two of the above (2(n+1)) and each
of your power cords goes to one each.

Which doesn't address the failure of one piece of equipment.  Of course, if
you're dual chorded from your server through fully redundant switch gear to
multiple, diverse vaults then a single ATS failure shouldn't affect you.

Regards,

Mike



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