Cisco 7604 Configuration Guide - Page 284

preempt, replication http

Page 284 highlights

Configuring Failover Chapter 14 Configuring Failover that have the unit as a priority do not become active on that unit unless manually forced over, a failover occurs, or the failover group is configured with the preempt command. The preempt command causes a failover group to become active on the designated unit automatically when that unit becomes available. Enter the following commands to configure preemption for the specified failover group: hostname(config)# failover group {1 | 2} hostname(config-fover-group)# preempt [delay] You can enter an optional delay value, which specifies the number of seconds the failover group remains active on the current unit before automatically becoming active on the designated unit. Enabling HTTP Replication with Stateful Failover To allow HTTP connections to be included in the state information, you need to enable HTTP replication. Because HTTP connections are typically short-lived, and because HTTP clients typically retry failed connection attempts, HTTP connections are not automatically included in the replicated state information. You can use the replication http command to cause a failover group to replicate HTTP state information when Stateful Failover is enabled. To enable HTTP state replication for a failover group, enter the following command. This command only affects the failover group in which it was configured. To enable HTTP state replication for both failover groups, you must enter the following command in each group. This command should be entered in the system execution space. hostname(config)# failover group {1 | 2} hostname(config-fover-group)# replication http Configuring Interface and Unit Poll Times You can configure the amount of time between hello messages when monitoring the health of the interfaces in a failover group. Decreasing the interface poll time allows failover to occur faster when an interface fails, but consumes more system resources. To change the default interface poll time, enter the following commands: hostname(config)# failover group {1 | 2} hostname(config-fover-group)# polltime interface seconds The unit poll time specifies the amount of time between hello messages sent across the failover link to determine the health of the peer unit. Decreasing the unit poll time allows a failed unit to be detected faster, but consumes more system resources. To change the unit poll time, enter the following command in global configuration mode of the system execution space: hostname(config)# failover polltime seconds Configuring Failover Criteria By default, failure of 50% of monitored interfaces causes failover. You can specify a specific number of interfaces or a percentage of monitored interfaces that must fail before a failover occurs. The failover criteria is specified on a failover group basis. To change the default failover criteria for the specified failover group, enter the following commands: hostname(config)# failover group {1 | 2} hostname(config-fover-group)# interface-policy num[%] When specifying a specific number of interfaces, the num argument can be from 1 to 250. When specifying a percentage of interfaces, the num argument can be from 1 to 100. 14-30 Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM OL-20748-01

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14-30
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM
OL-20748-01
Chapter 14
Configuring Failover
Configuring Failover
that have the unit as a priority do not become active on that unit unless manually forced over, a failover
occurs, or the failover group is configured with the
preempt
command. The
preempt
command causes
a failover group to become active on the designated unit automatically when that unit becomes available.
Enter the following commands to configure preemption for the specified failover group:
hostname(config)#
failover group
{
1
|
2
}
hostname(config-fover-group)#
preempt
[
delay
]
You can enter an optional
delay
value, which specifies the number of seconds the failover group remains
active on the current unit before automatically becoming active on the designated unit.
Enabling HTTP Replication with Stateful Failover
To allow HTTP connections to be included in the state information, you need to enable HTTP
replication. Because HTTP connections are typically short-lived, and because HTTP clients typically
retry failed connection attempts, HTTP connections are not automatically included in the replicated state
information. You can use the
replication http
command to cause a failover group to replicate HTTP state
information when Stateful Failover is enabled.
To enable HTTP state replication for a failover group, enter the following command. This command only
affects the failover group in which it was configured. To enable HTTP state replication for both failover
groups, you must enter the following command in each group. This command should be entered in the
system execution space.
hostname(config)#
failover group
{
1
|
2
}
hostname(config-fover-group)#
replication http
Configuring Interface and Unit Poll Times
You can configure the amount of time between hello messages when monitoring the health of the
interfaces in a failover group. Decreasing the interface poll time allows failover to occur faster when an
interface fails, but consumes more system resources.
To change the default interface poll time, enter the following commands:
hostname(config)#
failover group
{
1
|
2
}
hostname(config-fover-group)#
polltime interface
seconds
The unit poll time specifies the amount of time between hello messages sent across the failover link to
determine the health of the peer unit. Decreasing the unit poll time allows a failed unit to be detected
faster, but consumes more system resources. To change the unit poll time, enter the following command
in global configuration mode of the system execution space:
hostname(config)#
failover polltime
seconds
Configuring Failover Criteria
By default, failure of 50% of monitored interfaces causes failover. You can specify a specific number of
interfaces or a percentage of monitored interfaces that must fail before a failover occurs. The failover
criteria is specified on a failover group basis.
To change the default failover criteria for the specified failover group, enter the following commands:
hostname(config)#
failover group
{
1
|
2
}
hostname(config-fover-group)#
interface-policy
num
[
%
]
When specifying a specific number of interfaces, the
num
argument can be from 1 to 250. When
specifying a percentage of interfaces, the
num
argument can be from 1 to 100.