sample temp files that gets create in /var/spool/mail -rw------ jane mail _43398509485894865jane
I'm certain Dovecot didn't create this file at least directly.
-rw------ jane mail jane.lock
This is a dotlock and it can be created by Dovecot. You could also probably disable it. http://wiki.dovecot.org/MboxLocking http://wiki.dovecot.org/MailboxFormat/mbox
I have put the squirrelmail+dovecot offline now. It's hard to simulate the problem when I am the only one testing it. The issues came about, when I put it up online and the users started to use it.
Disabling it meaning remarking the following? #mbox_read_locks = fcntl #mbox_write_locks = dotlock fcntl
other users create these files randomly as well in /var/spool/mail, / var/spool/mail is an NFS mount.
Hmm. NFS is a pretty good suspect here. I know that in some situations it creates such temp files, although they're usually named .nfs.something. Are those files deleted or are they just lying around? What size do they have?
The _* files go away but for the .lock files, some of them don't go away and if they don't go, users no longer receives new emails, but can still send out emails. The temp file with _* has 0 file size, I don't remember what the .lock size it, I will see if I can simulate this again.