I've a two ASA5510 & configured Active/standby fO configuration in sub interfaces. But this configuration is not working. Please check the both ASA configuration & let me know what changes i have to take.
I've attached the ASA's configuration
Waiting for Valuable reply.
Glad you got your failover working correctly. As far as I know shutting down an interface via the config will not cause a failover. This is by design.
As far as the firewalls returning to the primary being the active firewall, this will not be done automatically and will require you to force the units back with the failover active or no failover active command depending on whether you connect to the primary or failed unit.