Cisco 500 Series, Руководство по настройке

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14-10
Cisco Security Appliance Command Line Configuration Guide
OL-12172-03
Chapter 14 Configuring Failover
Understanding Failover
Active/Active Failover
This section describes Active/Active failover. This section includes the following topics:
• Active/Active Failover Overview, page 14-10
•
Primary/Secondary Status and Active/Standby Status, page 14-11
• Device Initialization and Configuration Synchronization, page 14-11
•
Command Replication, page 14-12
• Failover Triggers, page 14-13
•
Failover Actions, page 14-14
Active/Active Failover Overview
Active/Active failover is only available to security appliances in multiple context mode. In an
Active/Active failover configuration, both security appliances can pass network traffic.
In Active/Active failover, you divide the security contexts on the security appliance into failover groups .
A failover group is simply a logical group of one or more security contexts. You can create a maximum
of two failover groups on the security appliance. The admin context is always a member of failover
group 1. Any unassigned security contexts are also members of failover group 1 by default.
The failover group forms the base unit for failover in Active/Active failover. Interface failure monitoring,
failover, and active/standby status are all attributes of a failover group rather than the unit. When an
active failover group fails, it changes to the standby state while the standby failover group becomes
active. The interfaces in the failover group that becomes active assume the MAC and IP addresses of the
interfaces in the failover group that failed. The interfaces in the failover group that is now in the standby
state take over the standby MAC and IP addresses.
Note
A failover group failing on a unit does not mean that the unit has failed. The unit may still have another
failover group passing traffic on it.
When creating the failover groups, you should create them on the unit that will have failover group 1 in
the active state.
Failover link failed at startup No failover Mark failover
interface as failed Become active If the failover link is down at
startup, both units become active.
Stateful Failover link failed No failover No action No action State information becomes out of
date, and sessions are terminated if
a failover occurs.
Interface failure on active unit
above threshold Failover Mark active as
failed Become active None.
Interface failure on standby
unit above threshold No failover No action Mark standby as
failed When the standby unit is marked as
failed, then the active unit does not
attempt to fail over even if the
interface failure threshold is
surpassed.
Table 14-1 Failover Behavior (continued)
Failure Event Policy Active Action Standby Action Notes