Cisco 7604 Configuration Guide - Page 266

Active/Active Failover, Failover Actions

Page 266 highlights

Understanding Failover Chapter 14 Configuring Failover Failover Actions In Active/Standby failover, failover occurs on a unit basis. Even on systems running in multiple context mode you cannot fail over individual or groups of contexts with Active/Standby failover. Table 14-1 shows the failover action for each failure event. For each failure event, the table shows the failover policy (failover or no failover), the action taken by the active unit, the action taken by the standby unit, and any special notes about the failover condition and actions. Table 14-1 Failover Behavior Failure Event Active unit failed (power or hardware) Policy Failover Active Action n/a Formerly active unit recovers Standby unit failed (power or hardware) No failover No failover Become standby Mark standby as failed Failover link failed during operation No failover Mark failover interface as failed Failover link failed at startup No failover Mark failover interface as failed State link failed No failover No action Interface failure on active unit Failover above threshold Interface failure on standby No failover unit above threshold Mark active as failed No action Standby Action Become active Mark active as failed No action n/a Mark failover interface as failed Become active No action Become active Notes No hello messages are received on any monitored interface or the failover link. None. When the standby unit is marked as failed, then the active unit will not attempt to fail over, even if the interface failure threshold is surpassed. You should restore the failover link as soon as possible because the unit cannot fail over to the standby unit while the failover link is down. If the failover link is down at startup, both units will become active. State information will become out of date, and sessions will be terminated if a failover occurs. None. Mark standby as failed When the standby unit is marked as failed, then the active unit will not attempt to fail over even if the interface failure threshold is surpassed. Active/Active Failover This section describes Active/Active failover. This section includes the following topics: • Active/Active Failover Overview, page 14-13 • Primary/Secondary Status and Active/Standby Status, page 14-13 • Device Initialization and Configuration Synchronization, page 14-14 • Command Replication, page 14-14 14-12 Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM OL-20748-01

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14-12
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM
OL-20748-01
Chapter 14
Configuring Failover
Understanding Failover
Failover Actions
In Active/Standby failover, failover occurs on a unit basis. Even on systems running in multiple context
mode you cannot fail over individual or groups of contexts with Active/Standby failover.
Table 14-1
shows the failover action for each failure event. For each failure event, the table shows the
failover policy (failover or no failover), the action taken by the active unit, the action taken by the
standby unit, and any special notes about the failover condition and actions.
Active/Active Failover
This section describes Active/Active failover. This section includes the following topics:
Active/Active Failover Overview, page 14-13
Primary/Secondary Status and Active/Standby Status, page 14-13
Device Initialization and Configuration Synchronization, page 14-14
Command Replication, page 14-14
Table 14-1
Failover Behavior
Failure Event
Policy
Active Action
Standby Action
Notes
Active unit failed (power or
hardware)
Failover
n/a
Become active
Mark active as
failed
No hello messages are received on
any monitored interface or the
failover link.
Formerly active unit recovers
No failover
Become standby
No action
None.
Standby unit failed (power or
hardware)
No failover
Mark standby as
failed
n/a
When the standby unit is marked as
failed, then the active unit will not
attempt to fail over, even if the
interface failure threshold is
surpassed.
Failover link failed during
operation
No failover
Mark failover
interface as failed
Mark failover
interface as failed
You should restore the failover link
as soon as possible because the
unit cannot fail over to the standby
unit while the failover link is down.
Failover link failed at startup
No failover
Mark failover
interface as failed
Become active
If the failover link is down at
startup, both units will become
active.
State link failed
No failover
No action
No action
State information will become out
of date, and sessions will be
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 will not
attempt to fail over even if the
interface failure threshold is
surpassed.