Please enlighten me how to do a "zero downtime upgrade" without rebooting my machine. Is there any other command that i need to issue other than "reload"?
Please help me.
To failover from the Primary PIX to the Secondary PIX without your sessions dropping, log onto the Secondary PIX and issue the command 'failover active'. If you do this via telnet your session will drop and you will need to log back in again.
There is no way to do this unless you have a fail-over unit configured. The downtime is very minimal when you reload (usually ~2 mins)