Very high density PC/rack required

I'm a server guy, specifically a blade guy and know my high-end gear well but I've got a new little challenge that I'm a bit lost on and you may be able to help.

I have a server spec that will do a specific job, I've looked at virtualising it and for dull reasons it's not going to work (not just yet anyway).

The machines have to have;

• dual core consumer processor with quite low power/heat (I'm thinking one of the newer i3's perhaps?)
• no more than 4GB of regular desktop memory
• two PCIe slots - one capable of taking a single-slot x16 GPU (not a 480 or similar, more along the lines of a 9800GT or 240 etc. - about 150W max), the other slot is for a custom low power DSP
• Built in regular dual-channel sound card
• a single GigE PXE/iSCSI-bootable NIC
• I don't need any USB, keyboard, mouse, sound I/O, SATA/PATA or DVD/hard-disk at all.
• They'll be running either XP or W7 (32-bit).

Now I need to get as many of these into a data centre as possible, I also want them as inexpensive as possible too (given the base specs), something I'm not normally bothered about therefore no expert in. I'll need several hundred or thousands of these machines, and have around an 8KW-per-rack limit (this could go up a little).

I normally use HP blades but even their BL2x220's work out very expensive and don't give me exactly what I need anyway. I looked at SGI/Rackable but they're all server-oriented with Xeons etc.

What are your thoughts? I know this isn't directly server related but it is for professional reasons. Thanks for your help.

Solution 1:

If you are building quite a few of them you might find designing your own case using something like http://www.protocase.com might be the way to go. I believe this is the route BackBlaze took: http://blog.backblaze.com/2009/09/01/petabytes-on-a-budget-how-to-build-cheap-cloud-storage/

Find a consumer or low end server motherboard with your needs and wrap a case around it. If your cards are short enough you might be able to get them into 2U. (I don't think I've seen right angle adapters for PCI-e).

You might also talk to your vendor, if you are a good customer and you need a few of these thing you might be able to get a custom option setup, especially if the vendor decides other customers will want something similar.

Solution 2:

How about taking the approach google takes (or at least took at one point). Skip the case, just get a motherboard + needed components and some shelves with some sort of insulation. On a normal 42U 4 post rack i'd imagine you could get 4 or 5 mini-itx type boards on one shelf.