Do not forget physical security (including, but not limited to, access control & surveillance -- different logs, videos, and people to control), local/municipal/state laws and regulations (e.g. fire control standards), personnel to manage all that sites (even third-party)... IMHO too much administrative burden. :-( Abraços, Marlon Borba, CISSP, APC DataCenter Associate Técnico Judiciário - Segurança da Informação TRF 3 Região (11) 3012-1683 -- Practically no IT system is risk free. (NIST Special Publication 800-30) --

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"vijay gill" <vgill@vijaygill.com> 31/03/08 2:27 >>> [...] On Sun, Mar 23, 2008 at 2:15 PM, <michael.dillon@bt.com> wrote:

Given that power and HVAC are such key issues in building big datacenters, and that fiber to the office is now a reality virtually everywhere, one wonders why someone doesn't start building out distributed data centers. Essentially, you put mini data centers in every office building, possibly by outsourcing the enterprise data centers. Then, you have a more tractable power and HVAC problem. You still need to scale things but it since each data center is roughly comparable in size it is a lot easier than trying to build out one big data center.

Latency matters. Also, multiple small data centers will be more expensive than a few big ones, especially if you are planning on average load vs peak load heat rejection models. [...]