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67-4
Cisco ASA 5500 Series Configuration Guide using ASDM
Chapter 67 Configuring Active/Active Failover
Information About Active/Active Failover
Failure to enter the changes on the appropriate unit for command replication to occur causes the
configurations to be out of synchronization. Those changes may be lost the next time the initial
configuration synchronization occurs.
Table 67-1 lists the commands that are and are not replicated to the standby unit.
Failover Triggers
In Active/Active failover, failover can be triggered at the unit level if one of the following events occurs:
• The unit has a hardware failure.
• The unit has a power failure.
• The unit has a software failure.
• You force a failover. (See Forcing Failover, page 67-17.)
Failover is triggered at the failover group level when one of the following events occurs:
• Too many monitored interfaces in the group fail.
• You force a failover. (See Forcing Failover, page 67-17.)
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 “Failover Health Monitoring” section on page 65-14 for more information about interface and
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.
Table 67-1 Command Replication
Commands Replicated to the Standby Unit Commands Not Replicated to the Standby Unit
All configuration commands except for mode,
firewall, and failover lan unit
All forms of the copy command except for copy
running-config startup-config
copy running-config startup-config All forms of the write command except for write
memory
delete debug
mkdir failover lan unit
rename firewall
rmdir mode
write memory show