Online Mailbox Format Conversion
--------------------------------
This page aims to help with the tasks around planned mailbox migrations to e.g.
mdbox. To perform this exercise with minimum service interruption a Postfix
check can be implemented to put mail for the accounts to be migrated on HOLD:
Postfix main.cf
---------------
---%<-------------------------------------------------------------------------
smtpd_recipient_restrictions =
[...]
check_recipient_access hash:/etc/postfix/recipient_maintenance,
permit_mynetworks,
reject_unauth_destination
---%<-------------------------------------------------------------------------
/etc/postfix/recipient_maintenance
----------------------------------
---%<-------------------------------------------------------------------------
user@domain.tld HOLD Planned maintenance
user1@domain.tld HOLD Planned maintenance
user2@domain.tld HOLD Planned maintenance
[...]
---%<-------------------------------------------------------------------------
Virtual Domain Aliases in Postfix can be easily used to populate the *List of
Recipients* to be converted (and to be queued on HOLD). The following basic
script helps populating the database and needs to be adapted to the actual
alias location:
---%<-------------------------------------------------------------------------
#!/bin/bash
set -e
ALIASES="/etc/postfix/virtual"
MAINTALIASES="/etc/postfix/recipient_maintenance"
doveadm user $1 || { echo 'user query failed.'; exit 1; }
sed -e "s/\(.*\)$1/\1/;s/[ \t]*$//; s/$/ HOLD Planned maintenance: account=$1/"
$ALIASES >>$MAINTALIASES
grep $1 $MAINTALIASES
postmap $MAINTALIASES
echo '[ Complete ]'
---%<-------------------------------------------------------------------------
Usage:
---%<-------------------------------------------------------------------------
$ maintalias.sh user@domain.tld
---%<-------------------------------------------------------------------------
Finally running *postmap recipient_maintenance* will create the database (in
case this part is not scripted).
Actual Migration
----------------
Disable new logins for the users by adding 'allow_nets=' to their userdb
records, effectively disallowing ALL nets. Close open sessions if any:
---%<-------------------------------------------------------------------------
$ doveadm who <user>
$ doveadm kick <user>
---%<-------------------------------------------------------------------------
Convert the mailbox using the backup option:
---%<-------------------------------------------------------------------------
$ dsync -u user@domain.tld backup mdbox:~/mdbox
---%<-------------------------------------------------------------------------
Adjust userdb entries (if required) to reflect new 'mail_location'. Clear the
'recipient_maintenance' DB and undo 'allow_nets=' entries for the migrated
users.
Finally release and requeue all mail previously held:
---%<-------------------------------------------------------------------------
$ postsuper -r [ALL]
$ postqueue -f
---%<-------------------------------------------------------------------------
(This file was created from the wiki on 2019-06-19 12:42)
Copyright 2K16 - 2K18 Indonesian Hacker Rulez