Ultimate Linux Box 2005
Let's just call 2005 the year of power management. Processor vendors made a big deal out of whitepapers about saving watts, and we heard a lot about power management at LinuxWorld Conference and Expo in February.
Did the industry start caring about global warming? Do IT CEOs want to eat swordfish more often, so they have to reduce the mercury emissions of power plants? Not quite. Today's server systems are packing more and hotter processors closer together, and customers' air-conditioning systems aren't ready for the strain. NASA had to install water cooling for its 10,240-processor Columbia cluster, as we showed in our January issue.
Every watt-hour you can save is heat that the customer doesn't have to deal with—3.6kJ, or 3.4BTU to be precise. With data centers full of blade servers, and 1U systems sporting as many as four processors, all that heat really adds up.
The Linux desktop greedily devours the scraps from the multibillion dollar Linux server market, and power consumption matters to us on the desktop too. Fans are loud. If you have better power management on your processors, they produce less heat, and you can run fewer fans or run the fans you do have more quietly. We took a different approach to fans, as you'll see later on.
Finally, of course, power matters on the laptop and on portable devices because of battery life. We'll leave the specifics of tweaking for maximum off-AC time to future articles.
We like Tyan motherboards, and companies that build custom Linux systems do too. The four-Opteron Tyan Thunder K8QS Pro came out just a little too late to make it into last year's Ultimate Linux Box. It's based on an AMD 8000 series chipset. When we say “chipset”, we mean a slightly different combination of hardware from an Intel-based system, though. The AMD64 way is to have an onboard memory controller per processor, give each processor its own bank of memory and link them with HyperTransport. Your AMD64 “SMP” box is really a mini-NUMA, and the “chipset” doesn't include the memory controller.
Last year, we used a Celestica A8440 bare-bones rackmount system as the basis for the Ultimate Linux box. Although starting with pre-integrated chassis and power supplies can be a great time saver, we realized that last year's box was on the loud side. This year, going back to our usual plan lets us pick everything else just the way we want it.
The K8QS Pro has two PCI-X busses, A and B. B is dedicated to two 133MHz-capable PCI-X slots, and A offers two PCI-X slots maxing out at 66MHz and one regular PCI slot. Onboard networking is two Broadcom BCM5704C Gigabit Ethernet interfaces, also on bus A.
There are all the regular PC ports, of which we're using the USB. SCSI and serial ATA are options, which you might want to keep in mind if you're planning to move this board into a more conventional server role when you're building your next Ultimate Linux Box.
Into this mighty board we plugged four of the best of the Opteron processors available at the time—the 846 HE, clocked at 2.0GHz and offering 1MB of L2 cache. See the sidebar for what became available while we were testing the system. We maxed out the system's main memory at 32GB.
Unfortunately for case shoppers, this board is SSI MEB size—13"x16" or 330.2x406.4mm. Not a problem for us because we're using a custom case this year, but the size does limit your case options.
When we're picking out a case for any custom-built system, Ultimate or otherwise, we usually get one that's quite a bit larger than what a big vendor would use for a comparable system. Smaller cases require less material and they're cheaper for vendors to ship, but since we like to tweak things, we get a case with more room to add devices and more room to work inside.
In order to have a completely silent system, you need to move storage outside the box. Options for doing this have changed a lot since the days when you had a choice between NFS and external SCSI enclosures connected by a 3-meter cable.
Today, you can make your drives go away using USB, FireWire, SCSI of course, Fibre Channel or the new ATA over Ethernet, which we covered in the June 2005 issue. A separate storage enclosure is no longer only an enterprise server-room thing.
Another option is simply to boot over the network and mount your storage via NFS. Since Penguin works with enterprise server-room hardware, and Fibre Channel does deliver impressive benchmark results, we went with it; an nStor 4320F Fibre Channel RAID enclosure, with Hitachi 18GB drives for the OS and larger Seagate drives for more storage.