HomeLab: How to Resolve Supermicro x8dti Fan Revving Issues

Supermicro-Hyper-Speed-6027AX-TRF-Front-Straight

Its Winter here in the Atlanta area, and the temperatures have been dropping down close to freezing. Likewise, the temperatures in my basement Homelab have been dipping below 66 degrees Fahrenheit, and apparently this makes my Supermicro Servers a bit unhappy.

A bit of background. When I set out to build my lab I decided to transfer my Supermicro X8DTI boards out of their stock rack mount enclosures (like what you see above) and into Standard EATX Towers. Running my boards in these towers allowed me to use large 120mm and 140mm fans for cooling. Sound wise this is a huge improvement over the stock 80mm fans used in the default enclosure as these larger fans can spin much slower than stock and still keep the system cool.

On several occasions I have been working in my office and have heard the fans in my lab servers revving up and back down again. At first I thought that maybe a fan was failing, and that one of my systems was overheating. Or that one of my systems had sucked in a bit too much basement dirt and dust. However neither were the case.

Specifically what was happening was this… The systems were running cool, so the fans would spin down to a low rpm and the system would then throw a low rpm threshold alert and spin the fan back up.When this occurs the system switches into some sort of “Critical Cooling Mode” and spins all the fans up to 100% for a few seconds. Rinse and repeat a few dozen times and you hear what almost sounds like an intoxicated neighbor playing with his new weedeater.

Using the IPMIitool command from my Linux desktop first logged into IPMI controller on my systems and checked to make sure that the fans were actually working properly. SDR is short for Sensor Data Repository

# ipmitool -H 10.1.0.104 -U admin -P <password> sdr list
Fan2 | 2176 RPM | ok
Fan3 | 340 RPM | ok
Fan4 | no reading | ns
Fan5 | 544 RPM | ok
Fan6 | 340 RPM | ok
…truncated…

Fan6 above is spinning mighty slow. Slow enough to drop below the Lower Non-Critical Value threshold. Rather than increase the speed of the fan as I have seen others do, I decided to lower the thresholds for this fan with the command below. Since Fan5 is also a bigun’ I decided to preemptively adjust its thresholds as well.

ipmitool -H 10.1.0.104 -U admin -P <password> sensor thres Fan4 lower 100 200 300
ipmitool -H 10.1.0.104 -U admin -P <password> sensor thres Fan5 lower 100 200 300

4 thoughts on “HomeLab: How to Resolve Supermicro x8dti Fan Revving Issues

    • 8000rpm – what size are your fans? 40mm I assume? If you need to peg your fan to a specific rpm your best bet might be to handle this from within the running OS. I know you can do this in Linux using fancontrol, and I would assume the same goes for Windows as well. ESX, well that’s probably not going to be an option.

      May I ask why you need your fans to spin at this specific RPM? Is the system running hot at 4k rpm?

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      • There are 8 92mm fans in the server, and while I don’t need a specific RPM, 8,000 seems like it would be a good start. There are 8 GPUs in this server and they are getting warm, so increasing the case fan speed would probably help it. I tried using fancontrol with lm-sensor but none of the fans get picked up.

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