We have a Postfix server here that is servicing about 70-80 active users. We have a single alias for all users in the system that we manage manually in /etc/aliases. Occasionally, email sent to this all users alias is deferred due to a number of reasons, some examples are given below:
Jan 25 12:02:15 mailserver postfix/local: 78D4619014D: to=, relay=local, delay=1956, delays=1936/0.01/0/20, dsn=4.2.0, status=deferred (cannot update mailbox /var/spool/mail/user1 for user user1. unable to create lock file /var/spool/mail/user1.lock: File exists)
Jan 25 13:42:14 mailserver postfix/local: 78D4619014D: to=, relay=local, delay=7954, delays=7936/0/0/19, dsn=4.2.0, status=deferred (cannot update mailbox /var/spool/mail/user2 for user user2. unable to lock for exclusive access: Resource temporarily unavailable)
Once the message is deferred it's redelivered to every person the alias sends mail to, even if they've already gotten a copy. So occasionally a message will make the rounds 3 or 4 times before it finally gets to every user successfully.
Has anyone had experience with this problem and what did you do to fix it?