Wednesday, August 7, 2013

Building a LittleFe Cluster

Since my times at university, I was always fascinated by high power computing, in particular parallel and vector computing. Of course, those machines are so expensive that it is very hard to get hold on a smallest of computing accounts.

The LittleFe project overcame one of the hurdles, namely the price, and came up with a really neat solution. The hardware of said project seems carefully selected, e.g. 12V power supply for the nodes, a GPU with CUDA cores, dual core 64bit processors, passive cooling etc. However, still this hardware has got its price.

Today, second hand hardware with relatively fast CPU are showing up on the market for cheap.
I focused a bit on finding suitable hardware with the possibility to compromise here and there.
It happens that a computer store in my vicinity happens to sell second hand mini-ITX board of this make
Jetway NF92-270-LF
for just €8.- including 1GB of SO-DIMM and a PSU.
This was to good to be true. The price easily beats even the "raspberry pi".

Well, of course I had to compromise:
  • no suitable GPU
  • single core ATOM N270
  • only 1GB
  • 32bit instruction set
 On the plus side:
  • passively cooled
  • 12V power supply
  • onboard Gigabit ethernet
  • onboard VGA (for configuring the nodes)
  • available daughter boards (e.g. Gb LAN)
Actually, the shop had 7 available, I bought all of them...
More data at the store.

The plan
is to arrange all 7 boards in a compact box running of 1 common 12V power supply. Taken the max. power consumption is 22W, this will add up to 154W for the boards. For a 12V system, this ends up in the range of 13A. I figure a regular PSU like this will do. In the beginning, I will certainly test with the PSUs coming with the boards.

The boards will be hooked up to an 8 port Gb switch, also located in said box. I happen to own a D-Link DGS-108, which is currently not in use. This thing rates 1A @ 5V, adding 5W to the system.

Potentially, depending how this develop, the system will have to be provided with one or two low noise fans, since heat worth about 160W will be created.

The 7 nodes will be the workers in a parallel (as opposed to massively parallel) system. Therefore, the box will not house any HDD.
The head node will be some similar individual computer equipped with GB LAN. Personally I would have enjoyed to use an Intel Atom netbook for this. However, the one I got have fast ethernet (100Mbps) only, which will compromise the cluster performance. Hence, the present choice is my trusty Asus Eee Box B202, which has got a Gb NIC and a WiFi-interface (see LittleFe page for explanation). Also, the B202 operates the same Atom N270 CPU as the Jetway boards, creating a nice symmetrical 8 core 8GB cluster.

Next step
=> pick up the ordered parts (tomorrow), build some sort of support structure for the boards and get started.
As always, I will take pictures and post those, together with progress reports, on this blog.

earlier this year, I build a 24 core cluster with AMD FX6100 processors, a project I never documented... I promise to do so in the near future.

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