nanog mailing list archives

Re: HE.net, Fremont-2 outage?


From: Tico <tico-nanog () raapid net>
Date: Wed, 04 Nov 2009 07:09:48 +0000

Joe Greco wrote:
Jeffrey Lyon wrote:
FWIW: http://www.he.net/releases/release18.html
No date on that 'press release' but the way back machine helps put it
somewhere in 2002. A lot of good this "Alameda" sized generator has done
recently...

http://web.archive.org/web/*/http://www.he.net/releases/release18.html

2MW isn't super huge or anything.  I would expect that, given the size
I have been led to believe HE is, they've got a lot more than that now.

My memory is that Alameda isn't huge, but it isn't small either.  I'm
not sure ..  ah, here

http://www.reuters.com/article/pressRelease/idUS179594+03-Apr-2009+BW20090403

peak 70MW

I'm not sure what the basis for the claim is that a 2MW generator is
"large enough to power the entire city of Alameda" ...  2MW gensets are
common enough in this business and it's possible to burn through 2MW in
a few hundred racks.  It isn't *that* much power.

A more conventional comparison might be to something like a hospital; one
of our local hospitals installed a 1.25MW generator which, IIRC, powers
all critical circuits.

http://hhenergyservices.com/electrical/photos.php?category_id=2845&subcategory_id=5027&id=196&number=7

Sometimes it is easier to picture things that way.

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.

Since this is the second time in recent history that this building has experienced a short power outage caused by ATS flakiness, perhaps keeping a small UPS in the cabinet isn't such a bad idea? Even if the distribution switches/routers lose power, at least the servers wouldn't have to go through fscks and DB integrity checks due to unplanned power loss, and the recovery time would be significantly faster.

Hell, for a 5 minute power outage, some of my services were down for 20 minutes. I'll happily take a 75% reduction in downtime for the cost of a UPS , though clearly redundancy across more reliable datacenters is a better solution.


... JG



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