Chapter 9 High Availability for FortiOS 5.0 : HA and failover protection : Synchronizing the configuration : Console messages when configuration synchronization succeeds
  
Console messages when configuration synchronization succeeds
When a cluster first forms, or when a new unit is added to a cluster as a subordinate unit, the following messages appear on the CLI console to indicate that the unit joined the cluster and had its configuring synchronized with the primary unit.
slave's configuration is not in sync with master's, sequence:0
slave's configuration is not in sync with master's, sequence:1
slave's configuration is not in sync with master's, sequence:2
slave's configuration is not in sync with master's, sequence:3
slave's configuration is not in sync with master's, sequence:4
slave starts to sync with master
logout all admin users
slave succeeded to sync with master