MPCMM0001 Chassis Management Module Software Technical Product Specification 139
Fan Control and Monitoring
it can determine when a firmware upgrade/downgrade would affect the user defaults. When a fan
tray is inserted into the chassis the Cooling Manager checks the /etc/cmm/fantray.cfg to see if there
are recorded minimum and maximum values for that fan tray at that location. It will compare the
recorded minimum and maximum to the minimum and maximum values that the inserted fan tray
returns. If they differ from the Cooling Manager it removes all of the user defaults from the /etc/
cmm/fantray.cfg file.
16.13 Chassis vs. Fantray
In versions of firmware prior to 5.2, all cooling operations are performed on the chassis location (-
l). If there is more than one fantray in the shelf the Cooling Manager will apply all settings to every
fantray. Also, if the user gets the current fan speed he is returned the average fan speed of all of the
fantrays in the shelf.
In firmware version 5.2, all cooling operations will be performed on specific fantray locations (i.e.,
cmmget -l fantray1 -d listdataitems). With the exception of the deprecated operations from 5.1
there will be no fantray operations performed on the chassis location.
16.14 Legacy Method of Querying/Setting Fan Speed
The following section describes the legacy method of fan control, which was the only method
supported in versions of firmware prior to 5.2. The following method has been left in for legacy
support only, and is not a recommended method for doing fan speed control. This method will be
removed from the next generation of firmware.
Note: While the fanspeed setting in the CLI supports any integer between 0-100, the PICMG Set Fan
Level command for the MPCHC0001 chassis only supports integers between 20 and 100. This
means 0 in the CLI fanspeed dataitem corresponds to 20 on the PICMG command, 50 to 60, and
100 to 100.
By default, the CMM sets the fan speed to a value based on the Recommended Normal Operating
Level (Maximum Sustained Speed Level)–a value returned by the fan tray in response to the
PICMG Get Fan Speed Properties command. For example, in the MPCHC0001 chassis, the
Maximum Sustained Speed Level is 70, which translates to 62 percent in the CLI.
The user can set the fan speed to a value between 0 and 100 percent of the full speed through any of
the supported interfaces. Setting the fan speed from the CMM changes the fan speeds for all of the
fans in the chassis. Setting the fan speed to 0 sets the fans to PICMG fan level of 20.
The following command can be used to set the fan speed for all fans:
cmmset -l chassis -d fanspeed -v [0-100]
emergencyshutdown and localcontrol are additional settings that can be used with the fanspeed
dataitem. emergencyshutdown will shut down the fans and localcontrol will restore local control of
fanspeed to those fan trays that support local control.
Note: localcontrol is not supported on the MPCHC0001 chassis fan tray.