Dual Athlon setup
 

So it's time to upgrade my Linux server and I'm thinking about a dual-Athlon setup. I've never built an SMP system before though, and I'm not even sure it'd be worth it.

Dave, I know you have a dual-cpu machine or two.. any particular caveats to watch out for?

I use the server mostly for mail, web, ssh, and ftp servers, but also do a little development on the side. Would I just be throwing $$$ away by going with 2 CPU's? Is there anything special I'd have to do when installing (Red Hat 7.3), or when compiling, to make use of 2 CPU's, or does it pretty much "just work" out of the box?

Also, I have a 64-bit dual-channel SCSI card that's currently being used in a 32-bit box. Would I see a decent performance boost by using it in a 64-bit PCI slot? I'm using a 3x18GB Seagate Cheetah RAID-5 setup (w/ Linux kernel software RAID).

Any thoughts would be appreciated.

There are only two setups where I'd use a dual Athlon (and yes, I have one):

a) Heavy use desktop box
b) Heavy use server

If you're just serving some web pages, mail, ssh and the like, you'll probably do just fine with a single processor. Use dual for running a game server with multiple instances plus web, mail, ssh, etc. It's probably <b>not</b> worth it to spend the extra money.

If you did, however, everything would "just work" with Red Hat. It will install two kernels - 2.4.x and 2.4.x-smp. You'll select which one to boot with GRUB (and set the default as the SMP one) and you'll be good to go.

Dual processors are certainly fun for a fast desktop box or for a server that's going to be running a lot of processor intensive apps (like the one we're installing in Baltimore this week), but for the little stuff, you'll be fine with just one.

What I think I'm gonna do for now is get an SMP board (Tyan Tiger MPX) but only one Athlon MP chip. That way I get the 64-bit PCI slot for my SCSI card, and can use ECC memory (which Crucial has on sale right now... $60 for 256 MB).

So if I decide to drop in a second CPU in the future (in case I get more into development), what would I need to do in order to recompile the kernel for smp, or would it recognize it even after initial installation?

I doubt it would recognize it after initial installation. But you could install Red Hat's SMP kernel package (rpm -Uvh kernel-2.4.x-smp.i386.rpm or whatever it ends up being called) and, if necessary, add the proper line to GRUB and then just boot that kernel.

That coupon on the 256MB chip is only good for one, so if you're buying two, realize you're only getting half the discount. :)

Yeah, I saw that, but I'm pretty sure my brother and my brother-in-law both need a 256MB ECC DIMM as well. :)