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I have a HP DL380p G8 with all supported HP hardware installed, this includes 2 300gb SAS HDDs, 1 1.2TB SAS HDD, and a HP SFP+ add-in card for networking.

When the server is powered off and is still plugged in, fan #6 only runs at almost full speed. HP iLO does not report fan speeds (among other things) when the server is off.

Server is in power saver mode in both the bios and OS.

Anyone know why this one fan would be running and at such high RPM (relative to powered on state)?

  • BIOS power saving should be set to OS Controlled. This may or may not solve the immediate fan problem, but will solve a variety of other power management problems you are having or about to have. – Michael Hampton Jun 27 '21 at 21:07
  • Changed it to os controlled. No change to fan speed when off. Havent had any power management problems, but good to know. –  Jun 27 '21 at 22:02

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The SFP+ daughter card I had installed (HP Flexfabric Network Card) apparently ramps up a single fan (#6) to cool the card when the server is off.

Replaced the SFP+ card with a regular 4 port RJ45 NIC and the fans arent even spinning when the server is off.

Honestly, it doesnt make any sense why a single fan would need to be at such high rpm to cool a nic that should be seeing very little traffic and be running a lot cooler compared to a server with a workload running. The fan speed for #6 when the server is powered on (and the NIC is much more active) sits at 12% (barely audible).

  • It's easy to declare - if you have 6x fans running at a low RPM is the moving more volume at the same time as a single one with the same rpm – djdomi Jun 30 '21 at 04:45
  • Then why not have all 6 fans running at a low rpm when off if it moves more air? –  Jun 30 '21 at 18:01
  • Because its HP Logic, you don't need to understand, but its logic says to cool the component to protect from standing, non movement heat. I think it will be silenced after some minutes – djdomi Jul 01 '21 at 04:40