[Dovecot] Restarting dovecot-auth stops authentication

[Attila Nagy]

  On 11/18/2010 06:45 PM, Timo Sirainen wrote:
> On Wed, 2010-11-17 at 21:17 +0100, Attila Nagy wrote:
>
>> pop3-login: Error: net_connect_unix(pop3) failed: Connection refused
> Right. This is the main problem. So the question becomes why is the
> connection being refused.
I would really love to solve this now. :)
What connects here to what? pop3-login to the pop3 service?
My current config is:
# 2.0.8: /usr/local/etc/dovecot/dovecot.conf
# OS: FreeBSD 8.2-PRERELEASE amd64
auth_cache_negative_ttl = 0
auth_cache_size = 100 M
auth_cache_ttl = 1 days
default_process_limit = 2000
disable_plaintext_auth = no
info_log_path = syslog
log_path = /var/log/dovecot-errors.log
mail_fsync = never
mail_gid = 999
mail_location = maildir:~/Maildir
mail_plugins = " quota"
mail_uid = 999
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope 
encoded-character vacation subaddress comparator-i;ascii-numeric 
relational regex imap4flags copy include variables body enotify 
environment mailbox date
passdb {
   args = /usr/local/etc/dovecot/dovecot-ldap.conf.ext
   driver = ldap
}
plugin {
   autocreate = INBOX.Trash
   autocreate2 = INBOX.Drafts
   autocreate3 = INBOX.Sent
   autocreate4 = INBOX.Spam
   autosubscribe = INBOX.Trash
   autosubscribe2 = INBOX.Drafts
   autosubscribe3 = INBOX.Sent
   autosubscribe4 = INBOX.Spam
   mail_log_events = delete undelete expunge copy mailbox_delete 
mailbox_rename flag_change save mailbox_create
   mail_log_fields = uid box msgid size flags vsize from subject
   quota = maildir:User quota
}
protocols = pop3 imap lmtp
service anvil {
   client_limit = 8192
}
service auth {
   client_limit = 8192
   unix_listener auth-userdb {
     mode = 0600
     user = qmailldap
   }
}
service imap-login {
   client_limit = 8
   process_min_avail = 16
   service_count = 0
}
service imap {
   client_limit = 8
   process_min_avail = 16
   service_count = 0
}
service lmtp {
   inet_listener lmtp {
     port = 24
   }
   user = qmailldap
}
service pop3-login {
   client_limit = 8
   process_min_avail = 16
   service_count = 0
}
service pop3 {
   client_limit = 8
   process_min_avail = 32
   service_count = 0
}
ssl = no
userdb {
   driver = prefetch
}
userdb {
   args = /usr/local/etc/dovecot/dovecot-ldap.conf.ext
   driver = ldap
}
protocol lmtp {
   mail_plugins = " quota mail_log notify"
}
protocol imap {
   mail_max_userip_connections = 1024
   mail_plugins = " quota imap_quota autocreate"
}
protocol pop3 {
   mail_max_userip_connections = 1024
   mail_plugins = " quota autocreate"
}

I've raised pop3's process_min_avail, but I still get these errors. 
There is nothing more in the error log.

>> I've checked, auth's start time is yesterday, so it wasn't restarted. I
>> guess what remains is the resource limit (client_limit maybe?).
> If that happens, there should be a log entry. You can grep process_limit
> and client_limit from logs.
Nothing with those.
>> How does dovecot logs timed out LDAP lookups?
> "Connection appears to be hanging, reconnecting"
>
> I usually log errors to a different log file. Normally that file should
> be empty, so you can easily see all the errors and warnings that could
> be causing problems.
>
> log_path = /var/log/dovecot-errors.log
> info_log_path = /var/log/dovecot-info.log
Done that, but I only have these in the errors.log:
Dec 21 12:41:06 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:41:06 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:29 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused
Dec 21 12:43:30 pop3-login: Error: net_connect_unix(pop3) failed: 
Connection refused

What else should I check?
I'm not completely sure about that yet, but it seems these errors come, 
when there are a larger amount of cache flushes towards the disks, so 
maybe there is a congestion in some processes. But that would be fine if 
the authentication waits for these flushes, but this shouldn't propagate 
to the user as an error.

Thanks,