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phaxmohdem
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60 core Raspberry Pi 2 Cluster-in-a-box

Mon May 11, 2015 1:36 am

I finally got my Raspberry Pi cluster online tonight, and now feel the need to show off my handiwork :)

Short video walkthrough:
youtu.be/Ij1SSgrDdBc

The premise -- create a portable, self contained cluster of computers that only requires a single power cable and an Ethernet uplink cable to operate.

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The hardware:
  • 1x Cheap toolbox from Home Depot
  • 15x Raspberry Pi 2 Computer boards (1GB RAM ea.)
  • 15x 16GB class 10 MicroSD cards
  • Ubuntu 14.04 LTS image loaded on each
  • 300W SilverStone SFX power supply
  • Netgear 16 port Gigabit switch
  • 120mm Noctua Fan
  • Arduino Pro driving gratuitous power LEDs up top
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Lesson learned:
For the fan, the network switch, and the arduino/LEDs I created custom molex wire harnesses for each and plugged them straight into a standard molex 4-pin connector on the power supply. No drama there. The Raspberry Pis, however, ended up being much much trickier to supply with solid power. My initial attempt involved snipping the end off of 15 cheap micro USB cables and soldering all the red wires together, all the black wires together and connecting them to another custom molex harness. This failed miserably. Turns out that not all of the USB cables had red and black routed to the same pins on the micro-usb end :S. (if a cable was connected wrong on one end, they just corrected for it when hooking up the other end of the cable evidently). After figuring out which cables needed to be crossed to get the power coming out of the correct pin I soldered it all back up, plugged it in, and... fail.

With this configuration, the Pis turned on, but under any kind of load the voltage would drop too far below 5V and the Raspberry Pis would throttle to about half speed. Turns out the cable gauge was too thin to drive the RPis. Frusterated, I salvaged just the micro-usb tips from the cables and made new cables from scratch with 18 gauge speaker wire. I hooked these wires up to the 24 pin ATX cable (which has many 5V leads) via a custom harness and spread the load out so that no more than 4 Pis were fed from a single 5V harness wire at a time. With the 18 gauge wire I could probably have fed more than 4 per lead, but I didn't want to risk it since there were so many of them available. -- Success! Now all Pis operate at full speed under full load on all cores without throttling.

TL:DR -- wire gauge is important in a high-ish current 5V project like this.

Now... I just need to figure out what the hell to actually do with this thing :P
 
Dirge
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Re: 60 core Raspberry Pi 2 Cluster-in-a-box

Mon May 11, 2015 6:12 am

Hey congrats this looks like a really fun project. Can I ask what you have planned for it and what kinda performance you can expect from it?
FDISK /MBR
 
chuckula
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Re: 60 core Raspberry Pi 2 Cluster-in-a-box

Mon May 11, 2015 6:32 am

phaxmohdem wrote:
Now... I just need to figure out what the hell to actually do with this thing :P


If you build it, the apps will come!
That is a very nice looking setup you've got built there! I wish I had the time/money/skills to do something like that too.
4770K @ 4.7 GHz; 32GB DDR3-2133; Officially RX-560... that's right AMD you shills!; 512GB 840 Pro (2x); Fractal Define XL-R2; NZXT Kraken-X60
--Many thanks to the TR Forum for advice in getting it built.
 
Dirge
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Re: 60 core Raspberry Pi 2 Cluster-in-a-box

Mon May 11, 2015 6:51 am

I think the OP already has something in mind :wink: . Otherwise that 60 core Raspberry Pi 2 Cluster-in-a-box would make a rather geeky ornament. So phaxmohdem what kind of black magic will this box perform?
FDISK /MBR
 
phaxmohdem
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Re: 60 core Raspberry Pi 2 Cluster-in-a-box

Mon May 11, 2015 7:38 am

I'm honestly not 100% sure what it will end up doing. I built it mainly as a research tool so I can get experience developing algorithms that scale across clusters of computers without sending the electricity bill through the roof (only draws about 45W at the wall under full load). My first goal will be to write some basic benchmark tests that I can run on the cluster and on my normal desktop systems to see what kind of performance this actually brings to the table. After that I may play around with writing some data-mining algorithms, or try to learn how to use Hadoop, or set up HAProxy and see what kind of performance these offer as a small web farm.

Also in the back of my mind is the possibility of marketing more refined and scalable versions of the rig as a cluster development platform for academics and professionals. We'll see how my experiences programming the thing end up going. The jury is still out on whether or not this is anything more than an exercise in soldering at this point :).
 
Duct Tape Dude
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Re: 60 core Raspberry Pi 2 Cluster-in-a-box

Mon May 11, 2015 8:30 am

phaxmohdem wrote:
I'm honestly not 100% sure what it will end up doing.

This is my exact problem! I wish I had more excuses to build things, and anything I've come up with isn't good enough to justify additional hardware.

Anyway, well done!! It's interesting that you'd have enough power to boot the Pis but not enough power to run the cores full speed. Really a testament to how crappy the cheap USB cables are these days.
 
Deanjo
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Re: 60 core Raspberry Pi 2 Cluster-in-a-box

Mon May 11, 2015 8:54 am

Obligatory "BUT CAN IT RUN CRYSIS?" post. :wink:
 
phaxmohdem
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Re: 60 core Raspberry Pi 2 Cluster-in-a-box

Mon May 11, 2015 9:06 am

I used to be able to install Crysis on things, but then I took an arrow to the knee.
 
KillerKerns
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Re: 60 core Raspberry Pi 2 Cluster-in-a-box

Tue Jan 26, 2016 12:33 pm

phaxmohdem wrote:
I used to be able to install Crysis on things, but then I took an arrow to the knee.

Haha Skyrim!!! HUSFOODA
This project is very interesting because I have been trying to find a way to use multiple CPU and motherboards for all one super computer. Raspberry Pi is probably where I should start. But the pain of buying sucks. Being 15 isn't very convenient money wise.

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