- Robert Moskowitz:
What I am seeing is that many of the packages seem to roll the messages into some SQL database.
Do they?
My Dovecot setup uses the /home/vmail/doman/../{cur,new,etc} tree structure.
That's the classic Maildir format. Widely supported, works fine if file system nodes are not a scarce commodity. Dovecot supports other formats (see https://doc.dovecot.org/admin_manual/mailbox_formats/) as well, but I still use Maildir because it is required by Notmuch, which is my software of choice for handling all my mailing list subscriptions.
Personally, I would not use a relational database as a mail store unless specifically required by the mail system of your choice. Email is not organised in a way that benefits from a RDB.
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?
As far as migrating content is concerned, you're better off using some form of IMAP synchronisation. This method is not dependent on the underlying mail store format, and it preserves the IMAP flags for your existing messages.
-Ralph