Feb 182011
From Rage

The first round of components arrived for my Yocto Project and Linux Kernel development system. I haven’t built a system like this (piece by piece) since I started using laptops in 2002. I had to learn all the new terms for all the same architectural bits. Spec’ing out the system was an interesting experience, and I learned something about categories at Newegg. Finding quality components can be a real challenge as you first have to sort through all the neon-lights-and-acrylic-chassis-viewing-window-crowd junk. But, there is a short cut – the term is “server”. It’s great, select “Server” to narrow the search for memory, CPUs, and especially cases and CPU coolers and all the teenage-gamer-consumer crap goes away and you’re left with no-nonsense computing hardware. The heatsinks were under “server accessories” and not “cpu fans”.

So first, the specs:

The machine will be put to a variety of uses, but most of the time it will be used for two things. First, as a build system for the Yocto Project. We build for four architectures, a variety of machines, and several image types. A typical build takes two hours (we are working on reducing that) and as my primary area of focus is the kernel, I try to build as many architectures as possible as I change things. Once built, these images can be tested in qemu. Being able to build these quickly and keep all the build trees around to facilitate incremental builds is important to keeping productive.

Secondly, I’ll use this beast to continue to work on the futex subsystem, parallel locking constructs, and real-time. When it comes to catching locking bugs or identifying bottlenecks – there is simply no substitute for core count.

When it isn’t busy with either of the above, I hope to use this system to build and test the mainline and tip Linux kernel trees.

Back to the assembly. For this stage, I only have the chassis, motherboard, and memory. I’m having to wait a bit on CPUs and disks. The assembly was straight forward, but I obsessed about airflow and cable management. Supermicro matches their chassis to their motherboards, so the usual time spent mapping and aligning every LED and switch connector was replaced with single ribbon connector – very nice. I still read through the manuals to make sure I was getting everything right. Turns out the motherboard has a built-in speaker where the manual says the speaker header should be, fine. There is some ducting to keep air flowing from the front of the chassis, over the motherboard, and out the back. I made sure I routed the SATA cables clear of that. Finally, the 665W ultraquiet PSU is not modular, so I had to find a place for all the cables I didn’t use while minimizing obstructions to airflow for the chassis and the PSU itself. Some careful bundling and a couple wire ties seems to have wrapped that up nicely.

I also discovered that CPU1’s fan conflicts with the rear chassis fan. I have a choice: I can remove the rear chassis fan, or I can remove the fan from the CPU heatsink (which was made easy by Supermicro). I’m somewhat disappointed in Supermicro here. This is their motherboard, with their recommended CPU fans, in their recommended chassis. Fortunately, the rear fan is immediately behind CPU1, and likely moves as much, if not more, air with less noise. If I do remove the CPU fan, do I connect the chassis fan to the CPU1FAN header, or leave it connected to the generic FAN5 header? I was pleased that both chassis fans and the CPU fans are four-wire fans, meaning their speed (and therefore noise level) can be controlled by the BIOS depending on temperature.

This motherboard support IPMI 2.0, meaning it has a service processor and a full graphical KVM. I’ll be running this system headless connected via two gigabit links to my home network. I was very pleased overall with the quality of the Supermicro components, they are a significant step up from what I’m used to seeing in consumer computing and while not cheap, they were not particularly expensive either. Only time will tell, but I’m becoming a Supermicro fan… er…. enthusiast.

Next time: CPUs, HDDs, RAID setup and benchmarking!

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