email location - files or sql

[Robert Moskowitz]

I have been running a Dovecot based mail server for over 10 years and it 
is time (really past) to upgrade.

I really don't want to roll my own anymore.  Too much time and too many 
skills needed.  Time to retire.  But still want it 'in-house'.

What I am seeing is that many of the packages seem to roll the messages 
into some SQL database.  My Dovecot setup uses the 
/home/vmail/doman/../{cur,new,etc} tree structure.

Is there any pros vs cons on this that I can read?

Is there some nice packed mailserver I can drop on a Centos-arm server 
that has Dovecot under the covers and I can easily rsync my current mail 
store to it?

Mail-in-a-box looks interesting.  But I have not figured out its 
internals and if I have to worry about anything compiled for arm that is 
not part of the distro.

Thanks in advance for help.