Installation guide

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Device Manager Guide, Cisco ACE 4700 Series Application Control Engine Appliance

OL-26645-02

Chapter 11 Configuring High Availability

Understanding ACE Redundancy

Synchronizing High Availability Configurations with ACE Appliance

Device Manager

When two ACE appliances are configured as high availability peers, their configurations must be

synchronized at all times so that the standby ACE peer can seamlessly take over for the active ACE peer.

As the active and standby ACEs synchronize, the configuration on the standby ACE appliance can

become out of synchronization with the ACE Appliance Device Manager-maintained configuration data

for that ACE appliance.

When an ACE appliance is in a standby state, if you make configuration changes on the active ACE

appliance this change is also synchronized with the standby ACE appliance. However, when you access

the Device Manager GUI you will not observe the configuration changes on the standby ACE. Yet, if

you access the CLI on the standby ACE and display redundancy configurations using the show

running-config ft command in Exec mode, you will see these configuration changes.

As a result, it is important for you to manually synchronize the ACE Appliance Device Manager on the

standby appliance to observe the entire configuration. See the “Manually Synchronizing Individual

Virtual Context Configurations” section on page 4-82.

When the ACE appliance performs a context failover (proceeds from the Standby Warm state or Standby

Hot state) to the Active state), the new active ACE appliance auto-synchronizes the configuration and

updates the ACE appliance Device Manager GUI.

In a high availability pair, the two configured virtual contexts synchronize with each other as part of their

ongoing communications. However, their copies do not synchronize in ACE Appliance Device Manager

and the configuration on the standby member can become out of sync with the configuration on the ACE

appliance.

After the active member of a high availability pair fails and the standby member becomes active, ACE

Appliance Device Manager on the newly active member detects any out-of-sync virtual context

configurations and reports that status in the All Virtual Contexts table so that you can synchronize the

virtual context configurations.

For information on synchronizing some or all virtual context configurations, see the following topics:

• Manually Synchronizing Individual Virtual Context Configurations, page 4-82

• Manually Synchronizing All Virtual Context Configurations, page 4-83