On Friday MacCentral
that some researchers are finding Apple Power Mac G4s the wrong shape for clustering. Justin D’Onofrio, who works at a private K-12 school, agrees, but came up with his own solution that involves Apple’s late, underappreciated Cube.
“At the Chapin, we’re pressed for space, so I was looking for a way to fit as many servers as I could into the smallest amount of space,” he told MacCentral. “The G4 towers were too big, iMacs weren’t powerful enough, but the G4 Cube was just right. Well, almost. You still couldn’t stack them, and you had to give them proper ventilation or they would turn off automatically when the heat built up.”
The solution: retrofit the Cube with a cooling system akin to the types of modifications overclocked PCs have. D’Onofrio calls this the “C2” unit. What he did was:
Remove the metal Cube from its plastic shell.
Attached a small high-power fan to the front, which cools the RAM and other motherboard components.
Attached a large high-power fan to the rear, under the handle, which cools the entire heat sink assembly. Since the Cube is “separated” by the motherboard components, the two separate flows of air don’t interfere with each other.
Applied Artic Silver, a thermal compound, to the RAM chips, and added two aluminum RAM heat sinks. D’Onofrio also applied compound to the CPU in place of the thermal pad used by Apple.
Hooked the fans up to a DigitalDoc (a fan and temperature monitoring system). This is powered independent of the Cube, so if a fan should fail, you can swap it out without turning the Cube off.
“What I got was a G4 server that ran very cool, and that I could stack up,” D’Onofrio said. “Since the DigitalDoc unit can support up to eight fans, I was planning on having setups with one DigitalDoc per four Cubes. Space-wise, you’d have four G4s in the space that one G4 tower takes up. Perfect for clustering, since you can stack them to the ceiling without having to worry about heat build-up, etc.”
Of course, this was before Apple dropped the Cube, so that sort of puts a damper on the solution. Still, if anyone would like the nitty-gritty details on this project, they can
Grande Vitesse Systems (GVS), a supplier of integrated system solutions for mission critical data management, storage and distribution, offers
rack mounted G4s. GVS designs, develops, manufactures and installs server, storage subsytems and network solutions.
“We showcased at Macworld and had a huge response for our G4 rackmounted in at 2U and 4U enclosure,” Jon Andres of GVS told MacCentral.
Also, Mark Kriegsman, founder of Clearway Techologies, passes along his “quick, effective, and inexpensive way to stack G4s (and G3s):
Buy 1/2-inch adhesive-backed little rubber feet at the hardware store, four per machine.
Stick them onto one side of the case of a G4, and presto — the box can now lie flat on its side.
Multiple machines can now be stacked as high as you like.
“It’s a pain in the neck getting inside the machines on the bottom of the stack, but at a total cost of about $2 per machine, this is a great alternative if you don’t need to upgrade or repair the hardware too often,” Kriegsman told MacCentral. “We’ve been doing this since the Blue and White G3s originally came out with the round-edge design, and it works great.”
Finally, as MacCentral reader Ken Fanning points out, an interesting Web site about Macs and computer clustering is the
AppleSeed Personal Parallel Computing