Answer in line
For the second unit, do we have to configure the ip address of the interfaces and the other configuration or just Failover command ?
A: Just Failover command
Do we have to do 'no shutdown' to all interface in the second unit ?
A: You don't need it on all interface if I remember correctly. But if you are using lan based failover, you need make sure the failover interface is up on the secondary box.
For connecting Link cable and lan failover cable do we have to use crossover cable or it's work with direct cable ? (we don't have enough switch for that)
A: If you did not configure any speed/duplex, auto-negociation should be enabled by default which includes "Auto-MDI/MDIX feature" and you don't need crossover cable. Otherwise, you have to use crossover cable.
