Following some interest of our Pi4U project at a computer show we were at recently (RiscOS London), I thought I'd take a look here and see if anyone was interested - and to see if anyone was doing, or had done something similar.
In terms of purpose, we are using a bramble to act as a linux gateway cluster for our app Concept2View. 16 Pis replace 16 physical 4U servers which would undertake tasks such as upload to YouTube and create QR codes. The brief was to reduce heat production and energy consumption - as well as having a chance to play with the Pis in a commercial sense! (Admittedly, this had nothing to do with RiscOS, but we were using the Pis at the show for another purpose).
We wanted to either source or produce something that filled our requirements:
* fits into our 19" rack,
* built to a commercial standard (lego is great but not viable for our project),
* holds about 16 Pis,
* was cooled as appropriate,
* didn't look like a box of wires from an IT cupboard,
* and more importantly, used a suitable power supply -as opposed to a hungry standard ATX or 16 individual pimples.
Having trawled the usual suspects (and I'm sorry if we missed anyone that has created something like this already), we decided to make something using commercially available parts.
So far, our project has involved:
* modding a new 4U rackmount ATX case (hence it's name the Pi4U),
* installing 4 aluminium rails on which to mount the Pis
* purchasing 3x 40w power supply modules - this will ensure that if one goes, two thirds of our bramble still works and keeps our app up!
* producing a power panel that fits in place of the drive and switch bays containing 3 PSU switches and 16 Pi switches.
* installing an ethernet switch so the case connects with one ethernet cable (suitable for our purpose)
* Installing 3 low noise fans, just to move the air around.
We only needed to power the device, use an SD card and access the ethernet. so we weren't worried about running the HDMI or audio out. The 4U case quite happily accepts the ethernet switch, and I'm sure that for other purposes, you could install an HDMI switch or other form of extension switching without exceeding the 4U space.
If anyone is interested, we can share the pics and videos of the buildup. We're also wondering if there is a commercial interest in this project elsewhere and also if anyone has suggestions or thoughts?