Server Management Behavior; Thermal Monitoring; Fan Control; Figure 5-10. Temperature States - HP Integrity rx8620 User's & Service Manual

Troubleshooting

Server Management Behavior

Server Management Behavior
This section describes how the system responds to over-temperature situations, how the firmware controls
and monitors fans, and how it controls power to the server.

Thermal Monitoring

The manageability firmware is responsible for monitoring the ambient temperature in the server and taking
appropriate action if this temperature becomes too high. To this end, the ambient temperature of the server is
broken into four ranges: normal, overtemp low (OTL), overtemp medium (OTM), and overtemp high (OTH).
Figure 5-10 shows the actions taken at each range transition. Actions for increasing temperatures are shown
on the left; actions for decreasing temps are shown on the right.
Figure 5-10 Temperature States
Send Chassis Code
Send Chassis Code
Send signal to the OS
Send Chassis Code
Fan Speed = HIGH
On large temperature swings, the server will transition through all states in order. It may go to the following
state immediately, but each of the preceding actions will occur. If the temperature reaches the highest range,
the server will be shut down immediately by the manageability firmware.

Fan Control

There are three sets of fans in the system: those on the I/O bay, the front and rear fans that are connected to
the main backplane, and those on the cell boards. The front fans are run off of standby power, and will be
running any time AC input power is supplied to the server. All of the fans turn on when 48 V power is
supplied to the system.
As shown Figure 5-10, the fan behavior is related to the temperature state. The fans will be set to high speed
when the ambient temperature is anywhere above the normal operating range. The front and rear fans will
be set to high speed any time a chassis intrusion switch is triggered when removing a side cover.
Altimeter Circuit
The PCI-X backplane contains an altimeter circuit. This circuit is used to adjust the chassis fan speeds for the
operating altitude at power on and during MP initialization. The chassis fans consist of the nine front fans,
the twelve rear fans, and the six PCI-X I/O assembly fans. If an altimeter failure is detected, the information
is logged as an Event ID then propagated to the OS level to be picked up by monitoring diagnostics.
120
OTH
Shut Down 48v
OTM
OTL
Normal
Send Chassis Code
Send Chassis Code
Send signal to the OS
Fan Speed = NORMAL
Reset
Chapter 5