Five fan module slots accommodate five fan modules. Each fan module contains 2x80 mm fans that provide front-to-back airflow to cool the chassis. All five fan modules must be installed for proper cooling. The fans in each module create a negative pressure that is evenly distributed across the interface modules. If a fan module fails, do not remove it until a replacement is available. When a fan module is removed, the empty slot diminishes air flow in the places where it is needed, which can cause interface modules to overheat and shutdown. The system can operate with an inoperable, but present, fan module indefinitely, but it can only operate for a short period of time with one module removed.
The following figure shows the rear of the chassis with all five fan modules. Facing the rear, the fan modules are numbered Fan 1 through Fan 5 from left-to-right. Fan modules are hot-swappable.
Warning
Risk of personal injury
When you remove a fan module, wait for the fans to spin down before you fully withdraw the fan module. Be careful to keep your fingers out of the fan blades.
There are thermal sensors inside the chassis that monitor the temperature inside the chassis. The sensors send information regarding temperature readings to the central controller, which automatically adjusts the fan module fan speed to maintain the proper temperature. For example, when the central controller determines that the temperature readings of the sensors is decreasing, the fan module fan speed also decreases. However, if one of the fan modules fails or is temporarily removed, the central controller increases the speed of the other fan modules to provide maximum cooling to the chassis. The chassis can operate with a single fan module failure and still maintain uniform airflow across all module slots. When all fan modules are operational, the central controller, using internal temperature sensors, determines the speed of the fans.
Warning
Do not operate the chassis for more than a few minutes with a missing fan module. To ensure internal chassis air pressure is maintained and to avoid interface modules overheating and shutting down, leave a failed fan module installed until a replacement is available.
Alarms are triggered when the temperature exceeds the following alarm thresholds—Warning, Critical, and Shutdown.
Note
%d represents a number for either a sensor, slot, or temperature.
The following list shows the log messages for the three threshold types:
Warning—Temperature Sensor %d is (%d C) has exceeded the alarm threshold temperature (%d C).
Critical—Sensor %d slot %d temperature (%d C) exceeded the critical alarm threshold (%d C). Module will be shut down at (%d C).
Shutdown—Sensor %d in slot %d temperature (%d C) exceeded the shutdown threshold temperature (%d C). Module has been powered down.
Alarms are cleared when the temperature decreases 2° below the threshold temperature. The following list shows the log messages when an alarm is cleared:
Critical threshold—Sensor %d in slot %d overheat critical alarm cleared
Warning threshold—Temperature Sensor %d overheat temperature alarm cleared
You can use the following command to monitor the current temperature, and view the threshold values for Warning, Critical, and Shutdown.
show sys-info temperature
The following table provides a description of the various threshold limits:
|
Value |
Description |
|---|---|
|
Sensor Index |
Specifies sensor IDs from 1 to 5. There are five sensors on each module. |
|
Current temperature |
Specifies the current temperature sensor reading. |
|
Warning threshold |
Specifies the temperature at which an alarm is raised. |
|
Critical threshold |
Specifies the point at which a log message is generated. Action must be taken at this point otherwise the module is at risk of reaching the shutdown threshold. |
|
Shutdown threshold |
Specifies the critical maximum value when the module shuts down. Note:
A module must be powered on again when it returns to normal state after entering a shutdown state. Normal state is when the temperature is below the Warning threshold value, and there is no alarm on the system. |
The following table shows an example of the threshold values for each temperature sensor in degrees Celsius (° C):
NPB# show sysinfo sensor all Sensor Information Id Name Current(°C) Warning(°C) Critical(°C) Shutdown(°C) -------------------------------------------------------------------------------------- 1 CPU Core 35 85 90 100 2 TF2 MAC 41 75 80 95 3 TF2 Serdes1 49 80 85 95 4 TF2 Serdes2 46 80 85 95 5 TF2 Serdes3 48 80 85 95 6 TF2 Serdes4 47 80 85 95 7 LC1 PHY MAX 65 115 120 125 8 LC1 QSFP MAX 38 63 68 73 9 LC2 PHY MAX 60 115 120 125 10 LC2 QSFP MAX 25 63 68 73 11 LC3 PHY MAX 65 115 120 125 12 LC3 QSFP MAX 31 63 68 73 13 LC4 PHY MAX 64 115 120 125 14 LC4 QSFP MAX 30 63 68 73 15 LC5 PHY MAX 66 115 120 125 16 LC5 QSFP MAX 33 63 68 73 17 LC6 PHY MAX 57 115 120 125 18 LC6 QSFP MAX 0 63 68 73 19 LC7 PHY MAX 53 115 120 125 20 LC7 QSFP MAX 0 63 68 73 21 LC8 PHY MAX 52 115 120 125 22 LC8 QSFP MAX 0 63 68 73 23 DIMM1 39 80 85 0 24 DIMM2 35 80 85 0 25 DIMM3 36 80 85 0 26 DIMM4 34 80 85 0 27 SSD 40 80 85 0
Each fan module contains two fans. Use the following command to monitor the status of each fan in all five cooling modules:
show sys-info fan
NPB# show sysinfo fan Fan Information Id Status RPM Percentage SpeedLevel Direction -------------------------------------------------------------------------------------- 1 Up 5800 33 LOW FAN_DIR_F2B 2 Up 5800 33 LOW FAN_DIR_F2B 3 Up 5900 33 LOW FAN_DIR_F2B 4 Up 5800 33 LOW FAN_DIR_F2B 5 Up 5900 33 LOW FAN_DIR_F2B FAN_DIR_F2B - Fan Airflow Direction is FrontToBack FanSpeedLevel - <40%[LOW],40-70%[MEDIUM],>70%[HIGH]