Over the last year I've had a script moving old mail (120 days) into my annual archive folder. This is the first year I've done this with Dovecot, previously it was running against Cyrus.
There's nothing particularly clever: a few conditions to match, then "move message to" the appropriate archive folder. There's one for every year from 2000 to 2015. 2015 is just barely ahead of need. 2014 has about a year's mail in the cur directory.
The 2000-2013 folders were filled by Cyrus and were migrated over using IMAP Migrate. They're fine, and read normally.
The 2014 layout looks normal to me # ls cur dovecot-uidlist dovecot.index.cache dovecot.index.log.2 new dovecot-keywords dovecot.index dovecot.index.log maildirfolder tmp
Permissions are the same as every other folder, as is owner: drw-r----- 2 vmail vmail 9.6K Apr 12 21:13 cur
and # ls | wc -l 9822
I've checked with Thunderbird, Mulberry, Claws, and Sylpheed - none can read the directory.
The files look normal: 2014/cur 1426411329.M123928P26360.host.domain.com,S=3523,W=3591:2,R
More or less the same as a working directory: 2013/cur 1405500734.M958596P27867.host.domain.com,S=794,W=819:2,RS
I've run
# doveadm force-resync -u user .archives.2014
and nothing changed.
I'm at a bit of a loss since no client can read them, something like moving them to another folder and back is a little complicated. Any hints?