Supermicro Server: Turn off Fan A/B?

[oguruma]

I bought a used Supermicro Server with an X9DR-LN4F+ moterboard. It has slots for 3x 80mm labeled fans 1-3. It also has fans A and B. With nothing connected to the Fan A and B headers, the server enters fan failure mode and the other fans spin at full speed.

Fans A and B seem to be designed to cool PCI expansion cards, which this box doesn't have. I would like to be able to disable these two fans so that I don't spin up the remaining fans when A/B aren't connected.

I see no options for that in BIOs. I see fan speed control in IPMI, but no way to disable specific fans. I also don't see a jumper pins that would enable these fans.

Does anybody have any idea how to disable fans A and B?

 

[Spearfoot]

I own a system based on the same motherboard. How do you have your fans configured?

Do you have CPU fans installed? If so where are these plugged in?

What fans do you connect to FAN A & B?

 

[oguruma]

I own a system based on the same motherboard. How do you have your fans configured?

Do you have CPU fans installed? If so where are these plugged in?

What fans do you connect to FAN A & B?

Both of the CPUs have large heatsinks with Fans 1, 2 and 3 blowing from the front to back.

I don't connect any fans to A/B and that is the point.... I don't want to use those...

 

[Spearfoot]

Both of the CPUs have large heatsinks with Fans 1, 2 and 3 blowing from the front to back.

I don't connect any fans to A/B and that is the point.... I don't want to use those...

I misunderstood your initial post -- 'fan failure' threw me off. So your system goes into 'Full Mode' if you don't attach any fans to FAN A and FAN B? That's probably completely normal behavior, as these systems are intended to be installed in server rooms where noise isn't an issue.

I solved the problem by installing Supermicro CPU coolers with fans on both CPUs and connecting these to FAN A and FAN B, but not connecting the 4th pin so that the relatively quiet CPU cooler fans run constantly at full speed. Then I run a script that checks the CPU and hard disk temperatures and sets the mode to 'Full', 'Standard', or 'Optimal' as needed.

 

[oguruma]

I misunderstood your initial post -- 'fan failure' threw me off. So your system goes into 'Full Mode' if you don't attach any fans to FAN A and FAN B? That's probably completely normal behavior, as these systems are intended to be installed in server rooms where noise isn't an issue.

I solved the problem by installing Supermicro CPU coolers with fans on both CPUs and connecting these to FAN A and FAN B, but not connecting the 4th pin so that the relatively quiet CPU cooler fans run constantly at full speed. Then I run a script that checks the CPU and hard disk temperatures and sets the mode to 'Full', 'Standard', or 'Optimal' as needed.

Part of the problem is that I don't even really understand exactly where Fans A and B would go.... There is room in the chassis for 3 fans near the backplane (which blow across the MOBO). The heatsinks are a Supermicro factory setup, so no use of CPU fans seems to be intended....

My only guess is that Fans A and B are intended for fans mounted on PCI cards?

 

[Spearfoot]

Part of the problem is that I don't even really understand exactly where Fans A and B would go.... There is room in the chassis for 3 fans near the backplane (which blow across the MOBO). The heatsinks are a Supermicro factory setup, so no use of CPU fans seems to be intended....

My only guess is that Fans A and B are intended for fans mounted on PCI cards?

Yes, that's right -- they're for cooling auxillary devices. Does your system have a clear plastic air shroud mounted over the CPUs? Mine did upon purchase, but I pulled it out and added CPU heatsinks w/cooling fans, configured as I described earlier.

 

[JohnnyGrey]

Perhaps you could try looking into changing the fan threshhold values via ipmitool, or at least see what they are? See this article. (Not sure if this is valid for older than X10 boards) I had to mess with this on my X11 board due to my Corsair fans being able to spin much slower than a typical "server" fan would. I'm unsure why it needs fans on those ports, but perhaps an "ipmitool sensor list all" will shed some light.