I took down one of my Linux servers last night for a slight rattle in the case so I assumed something needed cleaning or replacement. This is a headless unit since I only SSH into the server for configuration from my LAN or Internet.

The system is very basic using an AGP nVidia 5900XT 128MB card. I notice that when I powered the server back on, the GPU fan was not spinning however is was connected to the card and seated properly. Is it normal for a Linux system or any system not to engage the AGP cards cooling fan if it is a headless unit? The card does feel warm as in it is generating some heat from getting power but I am just not sure. To my knowledge the GPU fan shoud be engaged as soon as the CPU fan starts spinning.

Any thoughts?

I'd say there is a short in the fan or power cable to the fan. As long as it doesnt' get too hot, I suppose your alright. I'd try and track down some type of fan just for safety sake.

I've never heard of a GPU fan not running because a monitor wasn't plugged in, so I believe there is a short somewhere.

Further to musicman_ace's post, the fans won't be controlled by your OS, be it Linux or Windows, and are powered by the system board itself, depending on where abouts you plug the fan into. Some plug into a connector on the graphics card, others use a system fan connector on the system board or 4-pin molex power through an adaptor. Definately sounds like the either the power cable or fan on the GPU, not anything to do with Linux. I'd still want to look at it, even if it's not always powering a monitor.