My “new” PowerEdge was way too loud. Like, jumbo-loud. I’ve chosen to replace all the fans with quieter models, but oh boy, this turned out to be a major pain! As always, I didn’t follow the most important rule when tinkering: do stuff incrementally, and test after each step. Well, maybe I’ll learn someday.
For reference, here the fan models:
|4x Memory/Disk, 120x120x32mm, PWM||Nidec Beta V TA350DC, M34789-35||Arctic F9 PWM|
|2x PSU, 60x60x25mm, Tacho||Nidec Beta V TA225DC, B34605-33||Akasa AK-192BKT-B|
|2x CPU, 60x60x35mm PWM||Delta AFB0612EHE||Everflow F126025BU|
I’ve changed all the fans in one go and ended up with a system that didn’t boot anymore. It didn’t even get to the end of the BIOS initialization, it shut down directly. I gathered that it must be the power supply’s fans (else I would have had a warning message on the POST). I’ve checked and I realized that I bought some fans with a build-in thermal control; a sensor that slows down the fan rotation. Well, as I had them already I hacked them up to ignore the sensor (cracked open sensor casing, soldered two pins together; no resistance acts as if the sensor measures a very high temperature).
Next problem was that all fans spun at full speed. Impressively noisy, even for a seasoned cluster admin as me (I could hear the vibration 2 floors below). The reason were swapped PWM and Tacho pins (as I’ve found out after trying for a night to install Dell OpenManage 6.4 on Ubuntu 11.04 64bit). I don’t know why, but I needed different PIN configurations that every other source I’ve found on the Internet. Here’s what I’ve used in the end (This is looking on the bottom of the connector):
| 2 | 1 |-+
| 4 | 3 |-+
So everything is exactly as in the datasheets, except the swapped Control and Sense pins. After I’ve swapped them, the server became quite quiet and I quite happy. :D Actually, my desktop is now more noisy. Argh! BTW, thanks a lot to Brent Ozar for his blog entry on making a power edge quieter.
Now I seem to have another problem: as reported by Brent Ozar and others
One problem shown above is that sometimes fans spin slow enough that they trigger Dell’s thresholds for slow-moving fans. Gotta figure out how to fix that for good one of these days.
Damn. Now I either have to find a way to make the fans a little bit faster or to change the threshold. See the follow-up post for more info on the threshold problem.