Cisco 7604 Configuration Manual page 270

Understanding Failover
Failover is triggered at the failover group level when one of the following events occurs:
•
•
You configure the failover threshold for each failover group by specifying the number or percentage of
interfaces within the failover group that must fail before the group fails. Because a failover group can
contain multiple contexts, and each context can contain multiple interfaces, it is possible for all
interfaces in a single context to fail without causing the associated failover group to fail.
See the
unit monitoring.
Failover Actions
In an Active/Active failover configuration, failover occurs on a failover group basis, not a system basis.
For example, if you designate both failover groups as active on the primary unit, and failover group 1
fails, then failover group 2 remains active on the primary unit while failover group 1 becomes active on
the secondary unit.
When configuring Active/Active failover, make sure that the combined traffic for both units is within the
Note
capacity of each unit.
Table 14-2
or not failover occurs), actions for the active failover group, and actions for the standby failover group
are given.
Table 14-2 Failover Behavior for Active/Active Failover
Failure Event
A unit experiences a power or
software failure
Interface failure on active failover
group above threshold
Interface failure on standby failover
group above threshold
Formerly active failover group
recovers
Failover link failed at startup
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM
14-16
Too many monitored interfaces in the contexts that belong to the failover group fail.
The no failover active group group_id command is entered.
"Failover Health Monitoring" section on page 14-19
shows the failover action for each failure event. For each failure event, the policy (whether
Policy
Failover
Failover
No failover No action
No failover No action
No failover Become active
Active Group Standby Group
Action Action
Become standby Become active
Mark as failed
Mark active as
failed
Mark active Become active
group as failed
Mark standby
group as failed
No action
Become active
Chapter 14 Configuring Failover
for more information about interface and
Notes
When a unit in a failover pair fails,
any active failover groups on that
unit are marked as failed and
become active on the peer unit.
None.
When the standby failover group is
marked as failed, then the active
failover group will not attempt to
fail over, even if the interface
failure threshold is surpassed.
Unless configured with the
preempt command, the failover
groups remain active on their
current unit.
If the failover link is down at
startup, both failover groups on
both units will become active.
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