[179897] in North American Network Operators' Group
Re: Rasberry pi - high density
daemon@ATHENA.MIT.EDU (Randy Carpenter)
Mon May 11 18:21:34 2015
X-Original-To: nanog@nanog.org
Date: Mon, 11 May 2015 18:21:32 -0400 (EDT)
From: Randy Carpenter <rcarpen@network1.net>
To: Peter Baldridge <petebaldridge@gmail.com>
In-Reply-To: <CAM91edhPV8yzosyDCmKu2Qt-41vfm2TVPskjnPDiXYDhkJKdxw@mail.gmail.com>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
----- On May 11, 2015, at 5:36 PM, Peter Baldridge petebaldridge@gmail.com wrote:
>>>> Pi dimensions:
>>>>
>>>> 3.37 l (5 front to back)
>>>> 2.21 w (6 wide)
>>>> 0.83 h
>>>> 25 per U (rounding down for Ethernet cable space etc) = 825 pi
>
> You butt up against major power/heat issues here in a single rack, not
> that it's impossible. From what I could find the rPi2 requires .5A
> min. The few SSD specs that I could find required something like .8 -
> 1.6A. Assuming that part of .5A is for driving a SSD, 1A/pi would be
> an optimistic requirement. So 825-1600 amp in a single rack. It's
> not crazy to throw 120AMP in a rack for higher density but you would
> need room to put a PDU ever 2 u or so if you were running a 30amp
> circus.
>
That is .8-1.6A at 5v DC. A far cry from 120V AC. We're talking ~5W versus ~120W each.
Granted there is some conversion overhead, but worst case you are probably talking about 1/20th the power you describe.
-Randy
