*) Why do you have to switch from LDAP to MySQL?
*) To switch from MySQL, the most important things are:

- Keep passwords.
- Keep same maildir directory structure.

Both 2 are easy if you're familiar with where these info are stored. I suggest you setup a virtual machine with MySQL backend for testing, should be easy to migrate. And of course it requires you to write some simple shell/python script to export some data from LDAP server.

*) For password, please check this tutorial:
http://www.iredmail.org/docs/password.hashes.html

Passwords for ldap are stored in SSHA by default, you can copy them directly and store them in SQL column "mailbox.password".

*) Maildir path are stored in LDAP attribute 'homeDirectory' of user object, and must be splited 3 columns in SQL backend: mailbox.storagebasedirectory, mailbox.storagenode, mailbox.maildir.

By the way, i offer paid support for migration if you want. You can contact me here: http://www.iredmail.org/contact.html

We have a short tutorial to show you how to backup/restore LDAP data on iRedMail server:
http://www.iredmail.org/wiki/index.php? … FAQ/Backup

And below are detailed documents to learn OpenLDAP if you're willing to:

- Official OpenLDAP Admin Guide: http://www.openldap.org/doc/admin24/
- A great book: http://www.zytrax.com/books/ldap/

aha, LDAP is not obsolete, and it's not slow. LDAP protocol is optimized for read access, but it's a little slower for write access -- compare to SQL database.

In iRedMail with OpenLDAP backend, OpenLDAP is used to store mail accounts, this is a good use case for using LDAP. because Postfix/Dovecot and other softwares read/query LDAP server a lot, but almost no write access.

If MySQL service is in heavy use on your server, maybe it's a good idea to store mail accounts in LDAP in your case -- to reduce read access to SQL server.