A/A failover "failover lan unit primary" vs "primary/secondary"
Can someone explain what is the purpose of the command 'failover lan unit primary' when we implement A/A failover?
I tried to understand its meaning by reading as many resources possible, but still I cannot make it clear into my mind.
From Cisco's config guides:
"Unlike Active/Standby failover, this designation does not indicate which unit becomes active when both units start simultaneously. Instead, the primary/secondary designation does two things:
•Determines which unit provides the running configuration to the pair when they boot simultaneously.
•Determines on which unit each failover group appears in the active state when the units boot simultaneously"
On the following link is mentioned the 'failover lan unit primary':
1 Determines which appliance provides the running configuration to the pair
2 On which appliance each failover group is active when they boot simultaneously
3 Determining on which appliance each failover group is active when both appliances start simultaneously is accomplished by configuring a primary or secondary appliance preference for each group
Can someone explain me the difference between points 2 and 3?
Thank you in advance