Oracle Sun Network QDR InfiniBand Gateway Switch, Руководство по обслуживанию, Страница: 33 / 96

Detecting and Managing Faults 25
Related Information
■
“Evaluate a Temperature Sensor” on page 24
■
“Temperature Out of Range” on page 25
Temperature Out of Range
Temperatures within the chassis are regulated by the fans. For the fan cooling to be
effective, the intake room air temperature must be below 25˚C.
When a temperature is too high, it can be caused by:
■
Air flow is insufficient – The fan speeds are too slow, the fans have stopped
spinning, or the fan is missing altogether.
■
Cooling air temperature is too high – No component can be cooled to a
temperature lower than the cooling medium itself. Additionally, as the cooling air
temperature increases, the air’s ability to remove heat diminishes.
■
Heat generated within a component is greater than that removed – The cooling
system was designed for a certain power dissipated by the components. When
those components experience high computing or throughput loads, or are
subjected to overvoltage situations when a voltage regulator fails, they generate
more heat.
For example, if the temperature at sensor target
/SYS/MB/T_I4A
is too high, then
the fans speeds (
/SYS/FAN
x
/TACH
) are collectively too low, the cooling air
temperature (
/SYS/MB/T_FRONT
) is too high, the voltage powering the I4 switch
chip (
/SYS/MB/V_I41.2V
) is too high, or the loading on the switch chip is too high.
When a temperature is too low, it is rarely a detrimental situation. There is an
exception, when the temperature of a component is the same as room temperature or
lower, there is a great possibility that the component is not functioning as expected.
For example, if the temperature at sensor target
/SYS/MB/T_I4A
is too low, as
compared to the cooling air temperature (
/SYS/MB/T_FRONT
), then the I4 switch
chip is being held in a state of reset, the voltage for the I4 switch chip
(
/SYS/MB/V_I41.2V
) is not being provided, or the I4 switch chip has
catastrophically failed.
/SYS/MB/T_SP
45˚C 25 to 60˚C
/SYS/MB/T_I4A
39˚C 25 to 70˚C
/SYS/MB/T_B0
48˚C 25 to 70˚C
/SYS/MB/T_B1
49˚C 25 to 70˚C
Temperature Sensor Target Typical Value Acceptable Range