In a BIG-IP high availability (HA) configuration,Auto-Syncis a device trust feature that automatically synchronizes configuration changesfrom the Active device to the Standby devicewithin a Sync-Failover device group.
Key principles from BIG-IP Administration Data Plane Concepts:
TheActive device is always the authoritative source of configuration
Configuration changes are intended to be madeonly on the Active device
WithAuto-Sync enabled, any time the Active device configuration changes, the system automatically pushes the configuration to all Standby members of the device group
Configuration changes made directly on aStandby device are not preserved
In this scenario:
The administrator modifies a Virtual Server on theStandbydevice
That change islocal onlyand does not alter the device group’s synchronized configuration
When Auto-Sync next runs (triggered by a change on the Active device or an internal sync event), theActive device configuration overwrites the Standby configuration
As a result, the configuration change made on the Standby device isundone.
Why the Other Options Are Incorrect:
A– The change is not undone only when another change is made; it is undone during the next Auto-Sync operation
B– Changes made on the Standby device are never propagated to the Active device
D– Auto-Sync does not merge or promote Standby changes into the HA pair configuration
Best Practice Reinforced:
Always perform configuration changes on theActive BIG-IP devicewhen Auto-Sync is enabled to ensure consistent and predictable HA behavior.
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