SCrappy Cluster
About
This project is one I’ve recently started after received a bunch of old unwanted computers from a local college. The plan is to connect them together beowulf-style with the hope that I can get better performance from a group of computers for my simulations than a single computer. This challenge is somewhat interesting to me since the computers in my collection are quite old (ranging from pentium mmx to pentium 4) compared to my fairly recent core 2 duo. Hence my name for this project. This project was inspired by the microwulf project, except instead of using commodity hardware I’m using free hardware so my performance per dollar = even better 
Problems Encountered So far
There are several problems that need to be addressed before I actually get this thing up and running.
Building a Case to House all of the parts
Microwulf Cluster
I am likely going to follow a design similar to that of the microwulf project for my case since its fairly cheap and compact compared to having an atx case for each pc. However I have found it slightly difficult to find plexiglass or similar material in my area that is strong enough and doesnt cost ridiculous amounts of money (If anyone knows where some is available in the KW area let me know).
Update (June 2009): Progress on the Case
After getting a bunch of old computers given to me by some friends I ended up having enough free time to give the case design a try. I went with some plexiglass form the local hardware store, however it was quite expensive (for a starving student anyway), so I cheaped out and bought some that was a bit too thin. With the weight of all the motherboards and power supplies the plexiglass sags a little, so I will not end up using the stuff I bought for the final version. Anyway here are some pictures of what I made anyways, I think I will stick with a similar size for the final version with thicker plexiglass and motherboards on the top and bottom of each slab.
SCrappy Cluster
Powering the Cluster
Originally, I was going to just have a separate power supply for each motherboad and plug all of these into a power bar. However I have a few friends in electronics who have suggested some way of connecting multiple boards into one power supply so I might investigate this possibility with an uber power supply split off to all of them at once (at least it would make for an easy on / off solution for the cluster).
Booting the Distributed OS
At first my plan was just to have one computer with a hard drive and use NFS to split up the disk space between all of the compute nodes. Unfortunately, more than half of the motherboards are so old that they do not support PXE through the network cards. My backup plan was to use a bunch of cheap USB sticks to give each PC a local “disk” with its own small operating system that communicates with the host machine. Unfortunately the motherboards in many of them also do not support this type of booting. So I’m left with two options. Either use some of the many old junky hard disks I have laying around in each of these computers or look into using some kind of openbios or linuxbios type of system and enable pxe booting through that somehow. I’m more attracted to the second option but I haven’t decided for sure yet.
Operating System / Tool Choice
Another major decision / problem is the choice of an operating system for this thing. There are several choices of distributions within Linux, Mosix or even a custom OS, then in terms of tools there is the MPI (message passing interface) of PVM (parallel virtual machine). I am personally in favour of creating a custom OS myself because I have been working on a toy OS lately and since my research area in wireless networks is in Load Balancing and Scheduling I think I could probably apply some of this to the Operating System for the cluster. I am especially interested in specialized load balancing so that the less capable nodes receive appropriate jobs in the scheduling. However this would almost require some way for the system to dynamically predict the complexity of the code which is about to be run. Additionally, this whole business of designed a operating system for this thing from scratch would likely mean it would take me 10 years to get this ancient hardware up and running
Cluster Computing Links / Resources
Here you can find related stuff I find either interesting or useful
- Microwulf Project
- Load Balancing Beowulf Cluster
- Cluster in an IKEA cabinet
- Collection of Microwulf-style clusters
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October 10th, 2008 at 2:43 pm
[...] I have added a project page for the SCrappy Cluster SHARETHIS.addEntry({ title: “Cluster Computer Case Suggestions?”, url: [...]