[Dovecot] dovecot: imap-login: Error: net_connect_unix(imap) failed: Resource temporarily unavailable

[Kurt Hockenbury]

Ok, we updated to dovecot 2.0.9, and we're still seeing the 
"net_connect_unix(imap) failed" problem happen around peak login time, 
9-10am.

  dovecot  -n
# 2.0.9: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.32-71.14.1.el6.x86_64 x86_64 Red Hat Enterprise Linux 
Server release 6.0 (Santiago)
auth_master_user_separator = *
auth_mechanisms = plain login
default_client_limit = 5000
default_process_limit = 5000
disable_plaintext_auth = no
mail_fsync = always
mail_gid = 501
mail_location = maildir:~/Maildir:INDEX=/var/indexes/%n
mail_nfs_storage = yes
mail_plugins = quota
mail_uid = 501
passdb {
   args = /etc/dovecot/passwd.masterusers
   driver = passwd-file
   master = yes
   pass = yes
}
passdb {
   args = /etc/dovecot/dovecot-ldap.conf
   driver = ldap
}
plugin {
   quota = maildir:User quota
   quota_rule = *:storage=200M
}
service anvil {
   client_limit = 15000
}
service auth {
   client_limit = 32768
   unix_listener /var/spool/postfix/private/auth {
     group = postfix
     mode = 0660
     user = postfix
   }
   user = root
}
service imap-login {
   process_min_avail = 12
   service_count = 0
}
service pop3-login {
   service_count = 0
}
shutdown_clients = no
ssl_cert = </etc/pki/postfix/certs/nexus.pem
ssl_key = </etc/pki/postfix/private/nexus_key.pem
userdb {
   args = /etc/dovecot/dovecot-ldap.conf
   driver = ldap
}
protocol imap {
   mail_plugins = quota imap_quota
}