Fire, Power loss at Fisher Plaza in Seattle

William Herrin herrin-nanog at
Fri Jul 3 18:49:57 UTC 2009

On Fri, Jul 3, 2009 at 1:20 PM, Tomas L. Byrnes<tomb at> wrote:
> This begs the question of what basic parameters should be for a
> "carrier hotel" or co-lo. [...] The old NEBS standards were too much
> of a straightjacket.


There is a useful standard: ANSI/TIA-942. It offers specifications for
four tiers of data centers ranging from tier 1 (a basic data center
with no redundancy) to tier 4 (fully fault tolerant).
(the 2005 one)

Judging from
there's even research that projects what sort of annual downtime you
can expect for each of the tiers described by the standard.

When I walk into a data center, I make a habit of asking which tier
they achieve, at least for the HVAC and electrical systems. And then I
ask to see the components which the tier claim says they should have.

Bill Herrin

William D. Herrin ................ herrin at  bill at
3005 Crane Dr. ...................... Web: <>
Falls Church, VA 22042-3004

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