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Switchover Mechanisms
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m .
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Switchover Mechanisms
If the active supervisor module fails, the standby module automatically takes over. You can manually
initiate a switchover from an active supervisor module to a standby supervisor module.
Once a switchover process has started another switchover process cannot be started on the same switch
until a stable standby supervisor module is available.
If the supervisor modules are not in a stable state (online or powered down), a switchover will not be
Caution
performed.
HA Switchover Characteristics
An HA switchover has the following characteristics:
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Initiating a Switchover
To manually initiate a switchover from an active supervisor module to a standby supervisor module,
issue the system switchover command. Once issued, another switchover process cannot be started on
the same switch until a stable standby module is available.
To ensure that an HA switchover is possible, issue the show system redundancy status command or the
show module command. If the command output displays the
module, then the switchover is possible.
Cisco MDS 9000 Family Configuration Guide
8-2
Provides management redundancy using the Virtual Router Redundancy Protocol (VRRP). This
feature is also available in switches in the Cisco MDS 9100 Series and in the Cisco MDS 9200
Series.
See the
"The Virtual Router Redundancy Protocol" section on page
Provides switchovers if the active supervisor fails, the standby supervisor, if present, takes over
without disrupting storage or host traffic.
Directors in the Cisco MDS 9500 Series have two supervisor modules in the two center slots (sup-1
and sup-2). When the switch powers up and both supervisor modules are present, the supervisor
module that comes up first enters the active mode and the supervisor module that comes up second
enters the standby mode. If both supervisor modules come up at the same time, sup-1 becomes
active. The standby module constantly monitors the active module. If the active module fails, the
standby module takes over without any impact to user traffic.
It is stateful (nondisruptive) because control traffic is not impacted.
It does not impact data traffic because the switching modules are not impacted.
Switching modules are not reset.
Chapter 8
Configuring High Availability
36-16.
state for the standby supervisor
HA-standby
OL-6973-03, Cisco MDS SAN-OS Release 2.x
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