Mirroring

[Ramy M. Hassan]

Hi
My company bought new hardware for our mailserver, and I am now in charge of moving data from the old server to the new one. That data I want to move is about 200GB in a RAID-5 array , that's our clients emails in Maildir format. That's millions of small files that are continuosly changing as emails are delivered or users moving or deleting old emails.
To copy those 200GB offline , it would take several days. Apparently we can not stop email service for all that time. So I have to find a way to migrate data while keeping the service running.
I thought of setting up a mirror between old system and new one till data is 100% in sync then throw the old system away and the new one can take over, but I couldn't find a way to do that. I tryed rsync but without success. It crashed while building the files list.
While searching I found coda. I thought that it might help me but I am not sure of that. I don't know its limitations. My questions are , can coda really help in my case ? does it support such big volume size and huge nuber of files ? If not i will appreciate if anybody can point me to the right direction.

Best Regards
Ramy