Don't use dotlock files.
Method that generally works nice also is to start rejecting email for
the user when they are at 99% capacity, so you leave just alittle room
for that kind of thing left.
Quoting Joseph Tam jtam.home@gmail.com:
A mail user reported that he filled up his INBOX (despite reminders he was approaching his filesystem quota), and furthermore, he could not fix the situation because he couldn't expunge message he marked for deletion.
The dovecot logs revealed the cause
dovecot: imap(user): Error: open(/var/mail/user.lock) failed: Disc quota exceeded
This created an impasse where a user cannot free space because he needs to create a lock file that cannot be created because he needs free space. Is there any way out of this without administrator intervention?
Joseph Tam jtam.home@gmail.com