Mirroring a server

[Jason Crowe]

I manage a debian linux email server that is dieing a slow and painful 
death. It's a pentium 2 200 mhz machine that is under powered. I just 
got approved to get 2 identical machines (P4, 40 gig drive & 160 gig 
drive with a gig of ram). One will be our new mailserver and I would 
like the second on to be a drop in replacement. We are going to store 
all users mail on the server.

All that to ask the best way to mirror a server.  :) (at least it's not 
spam)

Thanks,
Jason