Building the Ultimate Linux Box
I always build with two disks: one system disk and one home disk. There are two good reasons to do this that have nothing to do with the extra capacity. One is the performance advantage of being able to interleave commands to different physical spindles. The other is I am quite a bit less likely to lose two disks at once than I am to trash a single one.
Let's suppose you have a fatal disk crash. If you have only one disk, good-bye Charlie. If you have two, maybe the crashed one was your system disk, in which case you can buy another and do a new Linux installation, knowing your personal files are safe. Or maybe it was your home disk; in that case, you can buy another home disk and restore it from backups (you did keep backups, right?).
Max out your memory. Lots of free memory will improve your virtual-memory performance. Fortunately, with RAM as cheap as it is now, a gigabyte or three is unlikely to bust your budget even if you're economizing.
You'll need a CD-ROM or DVD-ROM drive (you'll almost certainly be installing your Linux from it). You have a SCSI system, so get a SCSI CD-ROM. That's pretty much the end of spec, as there are only a few models of SCSI DVD-ROM, and SCSI CD-ROMs are a generic item.
We'll want a good, high-volume backup device, too. Large disks are so cheap that backing up your home directory to another disk seems an attractive alternative, but it's still good to be able to make backups that you can separate from your system and store off-site, in case of disaster. We'll go with a DDS tape drive. Even if you're building on the cheap, the less expensive CD-ROM burners aren't a good idea for mass backup. The problem is the per-megabyte cost of the media, which you can't reuse. Rick adds: “Tape is also faster, more rugged both in storage and in the process of recording (jostling a DAT drive doesn't destroy the ongoing backup), doesn't require gobs of scratch space for assembling image files and is way, way, easier to automate.”
Speaking of faster, one of the things you want most in a tape drive is transfer speed. This is a good reason to go with the newer DDS4 tape drives, which have speed that is typically half of the older DDS3 drives.
An increasingly critical aspect of machine design is handling the waste heat and acoustic noise of operation. Cooling is centrally important if you want your ULB to last because thermal stress from waste heat is almost certainly what will kill it. On the other hand, cooling makes acoustic noise, which human beings don't tolerate well. It's fair to say we've already reached the point at which the thermal load vs. cooling-noise trade-off is the effective limiting factor in the performance of personal machines.
So how do we manage this trade-off for a personal, desktop or desk-side machine? Being willing to pay a price premium for cool-running and low-noise parts can help a lot. Even clueful system integrators can't afford to do this because they're under constant competitive pressure to cut costs by using generic components. But, we aren't economizing here; we get to do it right.
Now that we've laid out the principles, it's time to do the practice—specify and build a machine.
In July 2001, the clear standout choice for a ULB motherboard is the Tyan Thunder K7, model S2462 (see the Sidebar titled “AMD, SMP, AGP and LEDs: the Tyan Thunder K7 S2462”).
There are good and bad consequences of having your peripherals onboard. The good ones are that the board has fewer points of failure and will throw less heat. The downside is that integration could make fault recovery more difficult. You want to minimize the chance that a failure in one onboard component will require an immediate motherboard swap. On the S2462, all the onboard peripherals can be jumpered out or disabled from the BIOS setup screens.
Internal expansion space isn't very important anymore because two-drive bays will hold more disk than you'll ever need. External bays are more important; you want one CD-ROM, one tape, one floppy and perhaps a DVD drive. That's one exposed floppy bay, three exposed half-height 5.25" bays and two internal bays.
There are three other important things you want from a case: good airflow design, component accessibility and noise attenuation, in that order. Finally, you may want your case to look neat. Good airflow design is actually the best reason to buy a large case. You want plenty of room for cool air to flow around the heat-generating electronics.
Tyan's site lists cases that have been qualified with the S2462, so I shopped around for a full tower on that list. Antec's Performance Series offers a number of cases that Tyan qualifies, and the swing-out side panel and quick-release drive bays featured on all of them appealed to me. When my design evolved to include a DVD player and the front-panel controls for a sound card, I went with the SX1200, the full-tower version with seven exposed bays.
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