Switchover Mechanisms; Ha Switchover; Process Restartability; Synchronizing Supervisor Modules - Cisco DS-C9216I-K9 Configuration Manual

Switchover Mechanisms

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.
Switchover Mechanisms
When the active supervisor module fails, the standby module automatically takes over. You can also
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

When a standby supervisor module is in the HA-standby state, an HA switchover is possible. An HA
switchover has the following characteristics:
•
•
•

Process Restartability

Process restartability provides the high availability functionality in Cisco MDS 9000 Family switches.
It ensures that the process-level failures do not cause system-level failures. It also restarts the failed
processes automatically.
This vital process functions on infrastructure that is internal to the switch.

Synchronizing Supervisor Modules

The running image is automatically synchronized in the standby supervisor module by the active
supervisor module. The boot variables are synchronized during this process.
The standby supervisor module automatically synchronizes its image with the running image on the
active supervisor module.

HA Redundancy States

The following conditions identify when automatic synchronization is possible:
Cisco MDS 9000 Fabric Manager Switch Configuration Guide
7-2
Is stateful (nondisruptive) since control traffic is not impacted
Does not impact data traffic since the switching modules are not impacted
Switching modules are not reset
Chapter 7 Configuring High Availability
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