Date: Tue, 02 Dec 2014 00:13:40 -0800 From: perryh@pluto.rain.com (Perry Hutchison) To: aimass@yabarana.com Cc: erichsfreebsdlist@alogt.com, kudzu@tenebras.com, freebsd-questions@freebsd.org Subject: Re: OT: UPS for FreeBSD Message-ID: <547d74b4.qPmD4NU27Cup8Ccm%perryh@pluto.rain.com> In-Reply-To: <CAHieY7Rq6CBASdEkm_tNOuKF8kzK3_f6TCoQD=RzgHtbhCymHw@mail.gmail.com> References: <CAHieY7QGp2ELF-R91eu=vSrPsimVmVNJQ4kfucQ56PR7EEZmig@mail.gmail.com> <m57qdq$did$1@ger.gmane.org> <54777AB1.9010800@bluerosetech.com> <m581p1$65m$1@ger.gmane.org> <54779629.302@bluerosetech.com> <alpine.BSF.2.11.1411271433320.60866@wonkity.com> <5478BD4F.7020306@yahoo.com> <5478BEE6.30308@bluerosetech.com> <5478CC08.9090307@yahoo.com> <20141128204722.561f948e@archlinux> <5478F16A.80605@yahoo.com> <CABhTyc9m7fOoeV170dj=foAhmyYWphzc8KD8wBacu5gNRPhT%2BQ@mail.gmail.com> <54791d3a.w/pI0kak03d%2B3nKC%perryh@pluto.rain.com> <CAHu1Y71vVbdx6Yd1VbE7kb_8k9O5UG93RXEaORPU0tULCpMsCQ@mail.gmail.com> <20141129113405.3d1bd1d6@X220.alogt.com> <54798883.saa13h6lE6rPwZCf%perryh@pluto.rain.com> <20141130212746.6d5eaf1f@X220.alogt.com> <547bd5bd.dKE49fHIj28ERZyT%perryh@pluto.rain.com> <20141201140037.584faf7e@X220.alogt.com> <CAHieY7Rq6CBASdEkm_tNOuKF8kzK3_f6TCoQD=RzgHtbhCymHw@mail.gmail.com>
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Alejandro Imass <aimass@yabarana.com> wrote: > ... at high power you would still need to employ high voltage to > decrease loss in the distribution, or you would need to employ > ridiculously large conductor bars to be able to distribute > low-voltage DC even in the most modest data center ... Oh, for Pete's sake! What part of "integrate a UPS with the PSU" (http://lists.freebsd.org/pipermail/freebsd-questions/2014-November/262603.html) is so hard to understand? I'm proposing that the individual PSUs be designed in such a way that a battery or two can be connected into each PSU, between the rectifier and the regulator. The cables between the PSU and its batteries would be maybe a foot long (if the batteries are mounted adjacent to the server, say in the next rack slot above or below) -- or up to a couple of meters long if all the batteries were housed in the bottom part of the rack with all the servers above -- and the conductors would not need to be much (if any) heavier than those connecting the regulator outputs to the circuit boards. Of course, if one insists on serving a whole data center (or even just one full server rack) from a _single_ UPS, that UPS is going to be a massive piece of equipment and the power distribution to its loads is going to require infrastructure commensurate with the amount of power involved. (It's also not all that reliable an arrangement, since the UPS becomes a single point of failure capable of taking down many systems.)
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