[Dovecot] Migrating from CourierMail to Dovecot

[Robert Moskowitz]

My current mail server is a Fedora12 system running 
postfix/mysql/couriermail/squirrelmail mix.

My new server is a Centos6 running 
postfix/mysql/postfixadmin/dovecot/roundcube mix.

I have 4 virtual domains and about 20 users; not a big setup by any measure.

Both servers have the same host name, but are currently on separate 
subnets.  My current plan is to stop services on the old server, switch 
them on subnets, rename the old server, and let 'slow users' drain the 
old server over a couple of days.

Then I got to thinking, could I migrate the /home/vmail/domain/user/new 
folders from the old to new server?  Not too many rsync commands to run 
to pull it off, but would that work? Is there something dovecot needs to 
do, and not just drop the files into the .../new folder?  Or is there 
some utility to run to properly place the mail files?

The file names are similar.  Courier file names look like:

1362661301.Vfd01I2422e6M121970.klovia.htt-consult.com,S=17381

Whereas dovecot adds a ",W=nnn" string to the file name.  I am assuming 
the content is otherwise the same.

I would like to test out the migration, and then pull it off over a 
sunday.  Due to meetings and holidays, this won't happen until early 
April, so I have time to work out the details.

All guidance and pointers are greatly appreciated.