Forcing A Failover - Cisco 4700M Administration Manual

Configuring Redundant ACEs
Command
no peer shared-vlan-hostid
Example:
host1/Admin(config)# no peer
shared-vlan-hostid
Step 4
do copy running-config startup-config
Example:
host1/Admin(config)# do copy
running-config startup-config

Forcing a Failover

This section describes how to force a failover (switchover). You may need to force a switchover when
you want to make a particular context the standby (for example, for maintenance or a software upgrade
on the currently active context). If the standby group member can statefully becoming the active member
of the FT group, a switchover occurs.
During failover, the ACE sends failover traffic to destination addresses as Layer 3 unicast and Layer 2
Note
broadcast. As a result, you may encounter high CPU utilization in the interrupt context on the switch that
connects the two ACEs in the failover setup.
The switchover process exhibits the following behavior, depending on whether you perform the task
from the Admin context or a user context:
•
•
When you specify the ft switchover command to force a switchover, there may be brief periods of time
Note
when the configuration mode is enabled on the new active group member to allow the administrator to
make configuration changes. However, any configuration changes made during this time are not
synchronized with the standby group member and will exist only on the active group member. We
recommend that you refrain from making any configuration changes after you enter the ft switchover
command until the FT states stabilize to ACTIVE and STANDBY_HOT. Once the FT group reaches the
steady state of ACTIVE and STANDBY_HOT, any configuration changes performed on the active group
member will be incrementally synchronized to the standby group member, assuming that configuration
synchronization is enabled.
Prerequisites
To use the ft switchover command, you must disable preemption by using the no preempt command.
For information on the preempt command, see the
Cisco 4700 Series Application Control Engine Appliance Administration Guide
6-18
Admin context—If you specify an FT group ID, then the FT group specified by the group ID
switches over. If you do not specify a group ID, then the Admin context switches over.
User context—Because you cannot specify an FT group ID in a user context, the context in which
you enter the command switches over.
Purpose
(Optional) Removes the configured bank of MAC addresses.
(Optional) Copies the running configuration to the startup
configuration.
"Configuring an FT Group"
Chapter 6 Configuring Redundant ACEs
section.
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