Comments on an A64 in a server?

kokopelli · Post by **kokopelli** » Tue Jul 06, 2004 8:10 am

Hi folks, I've been lurking here for a while and finally decided to get an account and join in the fun.

I'm thinking of upgrading a server from a PIII-733 to an Athlon 64, probably 3000+ or 3200+. The reason I'm posting it here is that I'm curious if anyone else has done something similar. This server is running linux and currently handles email, web, forums, SQL, and so on. Nothing particularly heavy but the extra horsepower would be nice.

Ideally, the server would have the A64 running full blast when needed and step down using C'n'Q to the 800 or 1000 MHz when usage is low. This would definitely help with the power and cooling costs (since this isn't the only server in the rack, which is in a unfortunately poorly-ventilated closet.)

So, has anybody run Linux on an A64 or has it in a server-style environment? I'd really appreciate any comments/suggestions/etc.

Spod · Post by **Spod** » Tue Jul 06, 2004 9:10 am

Upgrading will probably improve performance, but I suggest you try to determine your bottlenecks - it's quite possible that you're limited by your network interface, or amount of RAM.

Post your specs, number of users, peak commit charge (see Task Manager > Performcnae), average disk queue length... I'm not an expert at this, but these are the sort of things you need to consider.

Aside from that, I heartily approve of the idea of an AMD64 chip in a server. Excellent performance for the price. Obviously only the Opterons are fully certified for server use, and they're the only ones that use ECC RAM and can do dual CPU, but for a basic system, an Athlon 64 is much better value.

SpyderCat · Post by **SpyderCat** » Tue Jul 06, 2004 9:37 am

I'm sorry to spoil the fun, but I think Cool'n'Quiet is only available using Windows.

kesv · Post by **kesv** » Tue Jul 06, 2004 10:14 am

SpyderCat wrote:I'm sorry to spoil the fun, but I think Cool'n'Quiet is only available using Windows.

CnQ is a function of the BIOS and should be controllable through ACPI (advanced configuration and power interface). Using ACPI is what most of those pretty windows guis do that MB manufacturers are providing.

Linux can use acpi features just fine as long as the manufacturer has followed the ACPI standard. Most new MBs are standard compliant but there are bound to be exceptions.

kokopelli · Post by **kokopelli** » Tue Jul 06, 2004 10:14 am

Following up on the previous two posts... ([edit] kesv snuck one in on me!)

The server is running Linux (Mandrake) so doing Task Manager > Performance would be somewhat difficult..

Sorry for not making that more obvious.

The server itself doesn't have any bottlenecks - I just have the urge to upgrade, and an A64 is definitely future proof for at least the next 3-4 years. And I can always go from 32-bit Linux to 64-bit Linux when those OS's roll out. The fact that said A64 is going to be donated or given at a low low price certainly makes things easier.

Concurrent number of users is not really a problem either.. the forums/SQL are probably the heaviest processes running, although I'm sure a handful of folks are compiling test programs or whatnot (slowly.....)

From what I've read about the Athlon64, the processor wants lower latency rather than higher bandwidth. Given the prices of RAM in the U.S. these days, would it be better to go with more RAM overall or a lower amount that has good timings?

And on the Cool'n'Quiet tip, from reading around here it seems that the Cool'n'Quiet feature is in BIOS... maybe the utilities that enable the OS's use of it are only in Windows at the moment? I could certainly be wrong, so feel free to cheerily trash that theory in favor of the correct one.

Thanks for the comments, and keep them coming!

kesv · Post by **kesv** » Tue Jul 06, 2004 10:25 am

kokopelli wrote: From what I've read about the Athlon64, the processor wants lower latency rather than higher bandwidth. Given the prices of RAM in the U.S. these days, would it be better to go with more RAM overall or a lower amount that has good timings?

Depends on your ram usage, doesn't it ? Try running 'free -m' and see what it says. Often databases like to have more ram to cache things, but if your databases are small having ram in excess of the size of your db does not improve performance much.

Naturally the amount of memory needed by your other software plays a role too, but from what you told about the setup it seems the database is the most important bit.

hydroxyhydride · Post by **hydroxyhydride** » Wed Jul 07, 2004 10:10 pm

If you are going to use an A64, why not get a 35W mobile A64 and forget about trying to make CnQ work in linux?

Putz · Post by **Putz** » Thu Jul 08, 2004 4:04 am

Of course Task Manager won't run in Linux! But "top" will.

koody · Post by **koody** » Thu Jul 08, 2004 5:15 am

Cool'n'Quiet aka powernow is at least partly supported by the kernel. I'm not sure how the daemons for regulating the cpufreq and voltage is coming along.

kokopelli · Post by **kokopelli** » Thu Jul 08, 2004 6:32 am

If you are going to use an A64, why not get a 35W mobile A64 and forget about trying to make CnQ work in linux?

*ahem* The fact that said A64 is going to be donated or given at a low low price certainly makes things easier.

I'm not buying the processor, it's being given to me. Hence I have no control over what it is. Unless you're willing to donate $200 so I can get the 35W mobile A64.

It appears that A64's aren't too common in Linux systems yet. Ah, the pioneering spirit.

Inexplicable · Post by **Inexplicable** » Thu Jul 08, 2004 7:36 am

It's pretty simple. If the server is mission critical, go with proven technology. That means 2.4 series kernel and a 32bit platform. If you don't mind risking a few problems or having to wait for some of the goodies, get the A64. I'm not on the market for a new machine right now and I'm tempted to buy one anyway. As it is, my favourite distro (Debian) doesn't support it yet.

koody · Post by **koody** » Thu Jul 08, 2004 7:53 am

After trying Redhat, Gentoo, Suse, Mandrake, Xandros and Lindows all I can say is that Debian is the one for me. Oh, and about the AMD64 port I'm sure you already know this, but if you don't here goes:
http://www.debianplanet.org/node.php?id=1115

Inexplicable · Post by **Inexplicable** » Thu Jul 08, 2004 8:05 am

Well, I wasn't aware the port was about to plop into unstable any day now if that's what you mean. This sure doesn't help me stay firm...

kokopelli · Post by **kokopelli** » Thu Jul 08, 2004 10:09 am

Good replies, thanks!

This isn't a mission critical server by any means - and isn't the NX bit only enabled for 64-bit kernels? I'm definitely leaning towards the 2.6 series and 64-bit enabled kernels... and I love Debian.

I run it on my personal server at home.

Two things I want to accomplish with this server:
1) Build an AMD64 server box, make it run Linux, make it do everything the current server does.
2) Build a quiet/cool server. Both practical and eminently braggable.

I wanted to do C'n'Q because it's been a big topic here recently, and I had hopes that Linux would be able to step down the CPU when it wasn't being used much. I may run that question by the AMD folks and report the results back here.

Spod · Post by **Spod** » Fri Jul 09, 2004 3:26 am

XP SP2 will support the NX bit, so a 64-bit kernel isn't required.
I wouldn't know if the only Linux kernels to support NX were 64-bit, however.
It's unclear whether anyone was confused about this or not, but to state it explicitly, you can use AMD64 chips in an entirely 32-bit setup. You don't need 64 bit software to get good performance from an AMD64 chip.