Adjusting fan speed
Introduction
Together with PowerEdge 12th generation servers, Dell introduced the fan speed offset setting enabling fan speed to be increased and decreased with respect to the optimal fan speed in accordance with the thermal profile settings. High power third party add-in cards - such as Netscout's "Sniddely" analysis card found on TruView Packet (TVP) and TruView Appliance (TVA) - need increased fan speed to provide additional cooling.
Netscout has decided to apply a thermal profile for maximum performance which leads to permanent maximum fan speed and a corresponding sound level of nearly 81dBA!
Solution
 | DO NOT set the Fan Speed Offset too low. The Sniddely analysis card needs additional cooling. Setting the Fan Speed Offset too low may compromise the hardware and void warranty. As guidance, the tempertature of the CPU should never rise above 55°C |
 | Dell changed the iDRAC configuration menu ever so slightly with every new release of the firmware. The way to configure this setting may not be exactly the same as described below. This article was written with iDRAC version 2.50.50 installed. |
Setting the fan speed offset
The thermal profile and fan speed offset can be configured via iDRAC Settings during boot or via the iDRAC Web UI.
iDRAC Settings:
- At boot, press <F2>
- Select iDRAC Settings, then Thermal all way down the list
iDRAC Web UI:
- Login
- In the left panel expand Overview > Hardware
- Select Fans in the left and Setup in the right panel
We recommend the following settings:
Termal Profile: Default Thermal Profile
Fan Speed Offset: High (+55%)
Controlling the temperature
After about fifteen (15) minutes, check the temperature of the CPU. It should not be above 55°C. Increase fan speed if needed.
iDRAC Web UI:
- Login
- In the left panel expand Overview > Server
- Select Power / Thermal in the left and Temperatures in the right panel
When the System Board Inlet Temperature changes, the fan speed should increase automatically.