PDC failover

Greetings all,

I am in need of centralized authentication in my office network and after having great success with a variety of TurkKey appliances, selected your PDC drop in replacement.

My only issue is with the apparent lack of syncronization with a backup domain controller.  I can't afford to have my users denied access to their resources in the event the PDC fails.  I know I can't be the only person to forsee this problem and I suspect someone out there has a reasonable solution.

Is this feature built in and I just didn't look hard enough?  Is scheduling a cron job to copy files from the primary to the backup possible?