You have up to 72 hours to replace one fan tray as long as the switch air-inlet temperature does not exceed
86° Fahrenheit (30° C). If the temperature exceeds 86° Fahrenheit (30° C), the switch will shut down in 3
minutes. If you remove more than one fan tray at a time, the switch can operate up to three minutes before
shutting down. To prevent a shutdown, remove only one fan tray at a time.
Note
Starting from Cisco NX-OS Release 7.2(0)D1(1), use the
hardware fan-tray maintenance-mode
[
long
|
medium
|
short
] command to prepare a switch for fan tray removal. By default, the fans run at 100 percent
speed for approximately 4 minutes to prepare for fan tray removal when the
hardware fan-tray
maintenance-mode
command is used. Starting from Cisco NX-OS Release 8.1(1), by default, the fans run
at 85 percent speed for approximately 4 minutes to prepare for fan tray removal when the
hardware fan-tray
maintenance-mode
command is used.
Use the
long
keyword to run the fans at 65 percent speed for approximately 9 minutes to prepare for fan tray
removal. Use the
medium
keyword to run the fans at 75 percent speed for approximately 6 minutes to prepare
for fan tray removal. Use the
short
keyword to run the fans at 85 percent speed for approximately 4 minutes
to prepare for fan tray removal. For more information about the
hardware fan-tray maintenance-mode
, see
Cisco Nexus 7000 Series NX-OS System Management Command Reference
The fan tray maintenance mode will be cancelled in the following cases:
• If a temperature alarm is present.
• Hot-inlet temperature (Sup inlet temperature >= 30 degrees Celsius)
• Fan-tray is absent.
• Post-cool period (time elapsed after fan tray removal) has crossed 4 minutes.
Fan tray maintenance mode is cancelled and fan speed is set to normal if fan tray
migration or replacement is completed within 2 minutes of using the
hardware
fan-tray maintenance-mode
command. If fan tray migration or replacement is
not completed within 2 minutes, the remaining fan trays run at 85 percent speed
for the next 2 minutes, and at 100 percent speed from then on.
Note
• Pre-cool period (time elapsed before fan tray removal) has crossed 1 hour and 9 minutes—The fan tray
has not been removed since the past 1 hour and 9 minutes during which the switch was ready for fan tray
removal.
The following example shows the syslogs that are generated when the fan speed increases due to a minor
temperature alarm:
2017 Apr 3 16:46:07 SWITCH %CARDCLIENT-2-SSE: XBAR:5 FABRIC ONLINE
2017 Apr 3 16:46:07 SWITCH %PLATFORM-5-MOD_STATUS: Fabric-Module 5 current-status is
MOD_STATUS_ONLINE/OK
2017 Apr 3 16:46:07 SWITCH %MODULE-5-XBAR_OK: Xbar 5 is online (Serial number: JAE1921079X)
2017 Apr 3 16:47:00 SWITCH %PLATFORM-2-MOD_TEMPMINALRM: Xbar-5 reported minor temperature
alarm. Sensor=1 Temperature=48 MinT
hreshold=20
2017 Apr 3 16:47:00 SWITCH %VSHD-5-VSHD_SYSLOG_CONFIG_I: Configured from vty by admin on
vsh.12644
2017 Apr 3 16:47:35 SWITCH %PLATFORM-6-PFM_INFO: Fan Zone 1 : Fan Speed will change from
Cisco Nexus 7706 Hardware Installation Guide
OL-31330-01
92
Installing or Replacing Modules, Fan Trays, and Power Supplies
Replacing a Fan Tray