Mini Cloud Computer

March 1, 2008 7:30 PM

Can you recommend a cheap way to build a computing cloud? Ok, maybe a computing breath of warm air on a cold day...

I'd like to have some on-demand computing power to play with. Right now I'm thinking I'll use the systems to render tiles for OpenStreetMap, but maybe I'll use it for protein folding or maybe I'll donate it to my alma mater and have their computer science department use it for something fun and exciting.

I've got the following in my Newegg.com cart:

• ECS AMD690GM-M2 AM2 AMD 690G Micro ATX AMD Motherboard - Retail
  Item #: N82E16813135049


• Transcend 1GB 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Desktop Memory Model JM800QLJ-1G - Retail
  Item #: N82E16820208321


• AMD Athlon 64 X2 4200+ Brisbane 2.2GHz Socket AM2 65W Dual-Core Processor Model ADO4200DOBOX - Retail
  Item #: N82E16819103243

Can anyone find a better balance of cheapness and speed?

I'm planning on buying parts for 2 machines to start with, using USB flash or network booting for storage and OS.

How about power? Is there a way to power multiple motherboards from one PSU? It sure seems wasteful to have N (very inefficient) PSUs running when one high capacity PSU should be able to power all two or three CPUs.

posted by yellowbkpk to computers & internet (14 comments total)

Why build a system, when you can spin up as many instances as you need, and only pay for what you use?
posted by b1tr0t at 7:32 PM on March 1

Computer motherboards run on DC power in various voltages. So yes, you can get a high efficiency power supply put together that will supply the different voltages to many computers via mains power, but I don't know of any off-the-shelf wiring connectors that you'd be able to use to splice the DC power output into the connectors required by the motherboards ... nor do I know how to calculate the proper amperage load and how to scale that as you scale up in number of nodes.
posted by SpecialK at 7:36 PM on March 1

b1tr0t, I played with EC2 and quickly spent enough to get to the point where purchasing my own computing power would be more economical. It's a very nice service once you find the Firefox plugin for it.

SpecialK, that's what I was thinking: someone must have come up with a way to use DC straight from a larger 48V or 24V power supply with local, cheap, DC-DC PSUs at the motherboard.
posted by yellowbkpk at 7:43 PM on March 1

Found This googling for "ATX Power Splitter". It's probably expensive due to the specialness of the device.

Also, if you want to save even more money per board, newegg has an board/CPU cobo box that costs just $49.
posted by delmoi at 7:51 PM on March 1

SpecialK, that's what I was thinking: someone must have come up with a way to use DC straight from a larger 48V or 24V power supply with local, cheap, DC-DC PSUs at the motherboard.

If you want DC-DC power supplies, then check out logicsupply. They have one that's just twice as expensive as the splitter cable I linked above. Btw, if you're lusting after stuff like this, check out this Pico ITX board. A whole PC mainboard with CPU in a 10x7.5 cm package. That's slightly smaller then 4x3 inches. You have to pay for the size, though. You're better off getting fully size boards for your money.
posted by delmoi at 7:58 PM on March 1

Note that building weird custom systems will make economic sense for small clusters. As your cluster grows, the cost to maintain oddball equipment will likely exceed the the cost of going with standard rackmount gear and power supplies.

A lot of sites have thousands of Dell servers, yet I don't recall Dell ever offering 48V powered servers. Cisco gear can often be bought with DC input, but that is because telecom switching stations often have 48V for the T1s and POTS gear.
posted by b1tr0t at 8:33 PM on March 1

I'll play Devil's Advocate and recommend the Mac platform:

Hardware - PowerPC units. G4 (Sawtooth) towers can be had for under $200 at PowerMax and a number of other outlets. The nice thing about these units is that they can use ATX power supplies without modification. Throw in ethernet cables and a bridge.

Software - OSes 8.6-OS x Leopard. take your pick. Download the available parallel cluster apps from Project Appleseed.

For less than $1000 US, you can have 4 machines synced together.
posted by Smart Dalek at 9:08 PM on March 1

For less than $1000 US, you can have 4 machines synced together.

Yeah, four obsolete systems. Exciting. Compare the benchmarks. The fastest G4 got a score of about 1047. The fastest AMD machine got a score of 3851, almost four times faster right off the bat. That's a phenom chip (With four cores). So yellowbkpk could get more performance with a single system (costing less then $400 complete) then he could with a bunch of old macs costing $1k.
posted by delmoi at 11:35 PM on March 1

Also, if you just want a lot of computing power, it makes sense to build a single monster PC. Get something like this this four socket AMD motherboard which will give you up to 8 cores on a single board. Unfortunately you need 8,000 series opteron chips, which are expensive. this board will let you run 2,000 series chips.

Anyway, you may get more bang for your buck if you build a single monster machine. You can buy these Tyan boards off buy.com, they don't sell 'em on newegg.
posted by delmoi at 11:42 PM on March 1

Before we moved to EC2 (you will too eventually if you're serious about this and don't need access to more than a few hundred GB of local data -- the maintenance and power costs and not trivial, but this was not your question) we were running a custom build based on a Q6600, 1GB RAM, an Asus P5B-VM, and a 500GB disk in a $40 case with a PSU. They booted off of a $10 USB stick into debian. Total cost per node was under $500 shipped. That's 4 cores at 2.4GHz.

Normally when people spec clusters they have a clear data path in mind and usually an architecture requirement. Do you need fast floating point or integer, any vectorization chipset, do you need strong interconnect or is it embarrassingly parallel, etc.. Are you running MPI, hadoop, your own code?

If you're just messing around (no shame there!) I recommend getting something like we did above, intel and asus are widely supported across the linux distributions, that motherboard is cheap, you'll need video to POST even if you never hook a monitor into it, and if you're just parallelizing by spawning processes the Q6600 is fast and cheap. Make sure you install enough RAM for four copies of your thing.
posted by neustile at 5:29 AM on March 2

post-post: I didn't see how cheap your specs were. Are you going for super cheap just to have more machines to play with? It's always more efficient cost-wise to pack higher powered "cores" per node than to have multiple nodes. Think of all the stuff a node requires: a case, PSU, hard drive, space on a shelf, power bill, switch space, setup time, failure points. If you spend more on the CPU/MB to get more cores/speed in a single machine you'll have overall better performance / $.
posted by neustile at 5:35 AM on March 2

By the way This Intel board costs just $475 on buy.com, it has 16 DIMM slots, and two Xeon sockets. And supports up to 128 gigabytes of RAM. Combine that with two quad-core Xeon chips and we're talking 8 cores chugging away. Two of These would cost just $465, bringing the total system cost too $940. And you would have the same number of CPU cores as your proposed system with four nodes, for less cost. And you'll only need to buy one case/CPU.

If you wanted to do cloud computing experimentation, you can probably setup virtual machines and still archive higher performance. And you'll use less electricity.
posted by delmoi at 2:13 PM on March 2

SMP boxes make a lot of sense if you are running an application where the nodes need to share memory. If your problem distributes trivially, then a SMP box will just give you more memory contention than a stack of smaller boxes.

Buying stuff and setting it up can be fun, but you really need to step back and look at your problem and choose the architecture that works right for it.
posted by b1tr0t at 5:57 PM on March 2

And you'll only need to buy one case/CPU.

Oops, I mean case/PSU.
posted by delmoi at 9:21 PM on March 2