I recently added a slave server to my single server installation and are having a few problems with mail. I loosely followed this guide to get things up and running: www.howtoforge.com/installing-a-web-email-and-mysql-database-cluster-on-debian-6.0-with-ispconfig-3 I had problems with logging into the imap server with authentication failure with existing email accounts on the slave server. I haven't added any new email accounts. After changing dbname= and user= in the /etc/dovecot/dovecot-sql.conf file to match the master server I could log in fine. Was this the right thing to do or should the credentials be in both databases? I am now getting a lot of these error messages in my mail logs: Error: Transaction log /var/vmail/....../Maildir/dovecot.index.log: duplicate transaction log sequence (31) So I have 2 dovecot instances working on the same files and even sharing there log paths (they are in the directory mirrored by unison). What have I missed here? How are conflicts prevented?