RPiCluster: Another Raspberry Pi Cluster, With Neat Tricks

New submitter TheJish writes "The RPiCluster is a 33-node Beowulf cluster built using Raspberry Pis (RPis). The RPiCluster is a little side project I worked on over the last couple months as part of my dissertation work at Boise State University. I had need of a cluster to run a distributed simulator I've been developing. The RPiCluster is the result. I've written an informal document on why I built the RPiCluster, how it was built, and how it performs as compared to other platforms. I also put together a YouTube video of it running an MPI parallel program I created to demo the RGB LEDs installed on each node as part of the build. While there have certainly been larger RPi clusters put together recently, I figured the Slashdot community might be interested in this build as I believe it is a novel approach to the rack mounting and power management of RPis."

Re: Slow Pi

[Anonymous Coward]

If the purpose was to make a fast computer you may have a point. But the need for this project was to have a lore cost cluster to run massively parallel/distributed software. A single or low number of cores (relativity). May not give the solution you want. By exemplem, if you have a fast algorithm that can has to be run in order with no parallelism it will run fast on your $1000 x86. But the only way to speed this up is to use a faster processor then your technology limited. If you derive a different algorithm that may be a bit slower but allows massive parallelism, then you can make the system faster by adding more hardware. This system is not about doing things fast, it's about seeing how things run on a cluster. If you used the x86 then you would get a wrong result faster.

Made for specific availability + project priority!

[girlinatrainingbra]

it looks like the purpose behind this project is to have an "always available" (to this Ph.D. student) 32-node cluster that is dedicated to doing the work which this dissertation student needs to perform in order to complete his Ph.D., and it makes sense to be able to do this for the cost of a single Xeon node in a larger beowulf cluster.
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This lets him escape the externalities which might impinge on his getting his own work done, like the big bad Beowulf cluster not being up or available when he needs it, or it being prioritized for someone else's project (say a professor who has tenure and more funding available). Those sorts of shenanigans would delay his work. So a 1/3rd speed cluster that's always available for your own project is a helluva good deal at 1/32 the cost of the big bad beowuilf cluster, eh? At least I think so!

Comms and network testing needs hardware!!!

[girlinatrainingbra]

Right, but a "vastly superior computing solution" for CFD or linear equations is one thing. Trying to simulate network communications activity for 32 or 33 nodes on a single compute node is probably slower than actually trying out the algorithms on dedicated hardware that instantiates an actual hardware network. Thus, for a project that tries out different networking and communications algorithms, a 3 times more expensive by your calculations might actually end up being 10 times less expensive, especially considering the locking and interprocess communications required in a multi-threaded simulation on a single compute node vs. actually running it on real hardware with 32 nodes and an ethernet network linking the 32 nodes.
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Especially considering that this system is going to be used for wireless communications protocols, the real hardware solution is IMHO the better way to go.

Re: Slow Pi

[TheJish]

You seem to be missing the point of this completely. ;) I needed a cluster to test some distributed programs (yes, you can test distributed programs inside a cluster). The cluster itself has nothing to do with my PhD work other than that it is a tool I created to ensure I could test the software I've been developing. As for providing a tutorial on how to do what I did, I was writing this to enable freshman engineers understand what was involved with building the cluster. Not everyone knows Linux, or how simple it is to build a Beowulf cluster.