Expiring old mails on (dovecot IMAPS) server side
Years ago, I was using gnus to read my mails: among other things, I liked the fact that it was, by default, as expected from a newsreader, only showing unread messages and properly expiring old messages after some time. Then, using KDE, at some point, I switched to Kmail because of this nice integration within the desktop environment. Obviously I had to configure it to remove old mails (expires) in a similar fashion.
Then Kmail2 arrived. I’m not able to use this thing. It either does not even start or start overly slowly and use up 100% of cpu time for minutes, whatever computer I’m using, whether it’s an old bold regular P4 or an Athlon II X4, whether I have 1GB RAM or 8. I gather it’s related to akonadi/nepomuk/whatever, stuff supposed to improve your user experience, with fast search and so on. Fact is it’s unusable on any of my computers. So I end up, these days, using Roundcube webmail, which is not that bad but makes me wonder whether it’s worth waiting for Kmail2 to be fixed and, worse, leaves me with IMAPS folders with thousands of expired messages that should be removed.
So this led me to consider doing the expires on the server side instead of client side, with my user crontab on the server. Logged on the server, I just ran crontab -e and added the following:
# dovecot expires (SINCE means: received more recently than) # not flagged and already read, 1 week old min 05 */5 * * * /usr/bin/doveadm expunge -u 'user' mailbox '*' SEEN not FLAGGED not SINCE 1w # not flagged nor read, 8 weeks old min 09 */5 * * * /usr/bin/doveadm expunge -u 'user' mailbox '*' not SEEN not FLAGGED not SINCE 8w # read junk, 2 hours old min 15 */5 * * * /usr/bin/doveadm expunge -u 'user' mailbox 'Trash/Junk' SEEN not SINCE 2h # unread junk, 2 days old min 25 */5 * * * /usr/bin/doveadm expunge -u 'user' mailbox 'Trash/Junk' not SEEN not SINCE 2d
(Obviously you want to replace user by your local user account and Trash/Junk by your relevant junk IMAP folder) . This setup could probably be enhanced by using flags like DRAFT and such – however, on my local server, no actual draft got properly flagged as such, so it’s better to rely on the basic mark FLAGGED.