I'm putting together a spec for a big(ger) memory x86_64 host, and I hope some of you-all can help. I'm looking for success stories of hardware that folks are using in production environments, preferably with CentOS 4, with more than 4GB of memory per CPU.
I know there are lots of mobos out there that can do this, but I'm looking for what folks really have running. Call me paranoid.
The target is SATA + n*GigE + 1CPU + 8GB memory, and I can consider other configurations. The incumbent system is a Xeon 8GB system running i686 CentOS 4.3 (what else?), with light CPU loading and very heavy IO loading (WD raptors are our friends).
Folks with deep(er) knowledge of x86_64 architecture, I'd also be interested in the trade offs between 1CPU w/8GB and 2CPUs each with 4GB. (E.g. what's the real cost of shipping data back and forth between the memory spaces of the two CPUs? How does the 2.6 kernel deal with the split memory space? etc...) The memory is all going to be used up in kernel buffers keeping bits of files in kernel memory.
Also, trade offs between Opteron and Xeon architectures, i686 vs. x86_64, bounce buffers, etc., for an application like this would be helpful.
The application is enhancement to a mirror server (mirror.cs.wisc.edu) here at UW-Madison.
Many thanks to all in advance. Private or public replies welcome.
Dave Thompson UW-Madison