Hey all.

We've got some users that live on our primary email server (which lives in our internal network) that we need to migrate to a second email server (which lives in our DMZ). Both servers serve our domain, example.com, but our first email server runs UW-IMAP, while our newer second server is running dovecot.

We need to get these users cleanly migrated over, with all of their emails, and we're trying to do so with the doveadm backup tool - figuring that it will probably "do" Dovecot better than a generic IMAP to IMAP tool. So far, no dice - we get the following error message:

Jul 13 16:00:00 doveadm(user@example.com): Fatal: All your
namespaces have a location setting. Only namespaces with empty
location settings are converted. (One namespace should default to
mail_location setting)

Here is the command I'm trying to run:

doveadm -c /etc/dovecot/dovecot-migration.conf -D -o imapc_user=user
-o imapc_password=password backup -Ru user@example.com imapc:

Here is the output of doveconf -n:

# 2.3.16 (7e2e900c1a): /etc/dovecot/dovecot.conf
# OS: Linux 4.18.0-372.16.1.el8_6.x86_64 x86_64 AlmaLinux release
8.6 (Sky Tiger)
# Hostname: example.com
auth_mechanisms = plain login
auth_verbose = yes
disable_plaintext_auth = no
info_log_path = /var/log/dovecot-info.log
log_path = /var/log/dovecot.log
mail_debug = yes
mail_location = maildir:~/Maildir
passdb {
   args = /etc/dovecot/passwd
   driver = passwd-file
}
postmaster_address = postmaster@example.com
protocols = imap lmtp
service auth {
   unix_listener /var/spool/postfix/private/auth {
     group = postfix
     mode = 0660
     user = postfix
   }
}
service lmtp {
   executable = lmtp -L
   inet_listener lmtp {
     address = 1.2.3.4 127.0.0.1 ::1
     port = 24
   }
   unix_listener /var/spool/postfix/private/dovecot-lmtp {
     group = postfix
     mode = 0666
     user = postfix
   }
   user = vmail
}
ssl_cert = </etc/letsencrypt/live/example.com/fullchain.pem
ssl_dh = # hidden, use -P to show it
ssl_key = # hidden, use -P to show it
ssl_prefer_server_ciphers = yes
userdb {
   args = username_format=%u /etc/dovecot/passwd
   auth_verbose = yes
   default_fields = uid=vmail gid=vmail home=/var/vmail/%u
   driver = passwd-file
}
protocol lmtp {
   lmtp_rawlog_dir = /tmp/dovecot/%u
   log_path = /var/log/dovecot-lmtp-debug.log
}

-- Tom Spettigue Staff Engineer (720) 406-5269 Zonit Structured Solutions www.zonit.com