rsync as root for mail servers?

[Chris Maness]

I plan on cutting over a server to new hardware, and I was wondering if 
I can add cert based login for root (how do I do this)?  This is so that 
I can use rsync as root to sync the mail spool and home directories.  
Will this work?  I am using sendmail and wu-imapd.

Thanks,
Chris Maness