About Clock Modules - Cisco MDS 9000 Series Configuration Manual

Managing System Hardware
This figure shows the numbering of the fans in the front fan module on the Cisco MDS 9513 Director.
Figure 9: Cisco MDS 9513 Front Fan Module Numbering
The rear fan module (DS-13SLT-FAN-R) on the Cisco MDS 9513 Director has only two fans. If a fan in the
rear fan module fails, the State field in the show environment fan command output only displays "failure"
and not the failing fan number.
This example shows a fan module failure on a Cisco MDS 9513 Director.
switch# show environment fan
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Fan
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Chassis
Chassis
PS-1
PS-2

About Clock Modules

All switches in the Cisco MDS 9000 Family have two clock modules: Module A (primary) and Module B
(redundant). The clock modules are designed, tested, and qualified for mission-critical availability with a
mean time between failures (MTBF) of 3,660,316 hours. This translates to a potential failure every 365 years.
Additionally, Cisco MDS 9000 Family switches are designed to automatically switch to the redundant clock
module should the active clock module fail.
OL-29291-02
Model Hw
DS-13SLT-FAN-F 0.3
DS-13SLT-FAN-R 0.3
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Cisco MDS 9000 Family NX-OS Fundamentals Configuration Guide
About Clock Modules
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