The low-end server

Last Updated on September 30, 2010 by Dave Farquhar

Here’s a good question: What should a small operation do when it gets fed up with its network and is tempted to just chuck it all and start over?
Well, my advice is to start over. But I don’t agree that starting over requires one to chuck everything.

We’ll start with the server. Chances are, these days, you need one. If you’re doing Web and e-mail, you absolutely need one. But to a lot of people, servers are a mystical black box that costs more money than a desktop PC but runs a similar operating system. And that’s all they know.

Here’s what you need to know: A corporate server is built to stricter tolerances than a desktop PC and sometimes uses higher-quality parts (common examples are ServerWorks chipsets instead of Intel chipsets, SCSI instead of IDE, and error-correcting memory instead of the cheap nonparity stuff). You also often get niceties like hot-swap drive cages, which allow you to add or replace hard drives without powering down or opening the case.

They’re generally also better tested, and you can get a support contract on them. If you’re running an enterprise with hundreds or thousands of people relying on your server, you should buy server-grade stuff, and building your own server or repurposing a desktop PC as a server ought to be grounds for dismissal. The money you save isn’t worth it–you’ll pay more in downtime.

But a dozen people won’t hit a server very hard. This Web site runs on a Dell OptiPlex Pentium II/450 workstation. A workstation is a notch above a desktop PC but a notch below a server, in the pecking order. The biggest difference between my Optiplex and the PC that was probably sitting on your desk at work a year or two ago is that my Optiplex has a SCSI hard drive in it and it has a 3Com NIC onboard.

A small office can very safely and comfortably take a reasonably powerful name-brand PC that’s no longer optimal for someone’s desk (due to an aging CPU) and turn it into a server. A Pentium II-350 or faster, outfitted with 256 MB of RAM, a SCSI host adapter and a nice SCSI hard drive, and a 3Com or Intel 100-megabit Ethernet card will make a fine server for a couple of dozen people. (My employer still has a handful of 200 MHz Pentium Pro servers on its network, serving a couple hundred people in some cases.)

This server gets hit about as hard as a typical small business or church office server would. So far this month I’ve been getting between 500 and 550 visitors per day. I’ve served about 600 megabytes’ worth of data. My average CPU usage over that time period is in the single digits. The biggest bottleneck in this server is its 7200-rpm SCSI disk. A second disk dedicated to its database could potentially speed it up. But it’s tolerable.

Hot swappable hard drives are nice to have, but with an office of a dozen people, the 5-10 minutes it takes to power down, open the case, swap drives, and close the case back up and boot again probably doesn’t justify the cost.

A business or church office that wanted to be overly cautious could buy the very least expensive sever it can find from a reputable manufacturer (HP/Compaq, Dell, IBM). But when you do that, you’re paying for a lot of power that’s going to sit there unused most of the time. The 450 MHz CPU in this box is really more than I need.

Jeremy Hendrickson e-mailed me asking about whether his church should buy a new server, and whether it really needed two or three servers, since he was talking about setting up a Samba server for file serving, Apache for Web serving, and a mail server. Running file and Web services on the same box won’t be much of a problem. A dozen people just won’t hit the server that hard. You just make sure you buy a lot of disk space, but most of that disk space will go to file serving. The database that holds all of the content on this site is only a few megabytes in size. Compressed, it fits on a floppy disk with lots of room to spare. Yes, I could realistically do nightly backups of my Web server on floppies. If floppies were at all reliable, that is.

I flip-flop on whether e-mail belongs on the same server. The security vulnerabilities of Web servers and mail servers are a bit different and it would be nice to isolate them. But I’m a lot more comfortable about a Linux box running both being exposed on the ‘Net than I am a Windows box running one or the other. If I had two boxes, and could afford to be paranoid, I’d use two.

Jeremy said his church had a P3-733 and a P2-450, both Dells, due for retirement. I’d make the P3 into a file/print/Web server and the P2 into a mail server and spend the money budgeted for a new server or servers to buy lots of disk space and a nice tape backup drive, since they’d get lots of use out of both of those. A new $1200 server would just buy lots of CPU power that’ll sit idle most of the time and you’d still have to buy disks.

As far as concern about the reliability of reusing older systems, the things that tend to wear out on older PCs are the hard drive and the operating system. Windows deterriorates over time. Server operating systems tend not to have this problem, and Linux is even more immune to it than Microsoft server operating systems. So that’s not really a concern.

Hard disks do wear out. I read a suggestion not long ago that IDE hard disks should be replaced every 3 years whether they seem to need it or not. That’s a little extreme, but I’ve found it’s hard to coax much more than four years out of an IDE disk. Dropping a new SCSI disk or two or three into an old workstation before turning it into a server should be considered mandatory. SCSI disks give better performance in multiuser situations, and are generally designed to run for five years. In most cases, the rest of the PC also has several years left in it.

Later this week, we’ll talk about Internet connectivity and workstations.