[Dovecot] Dovecot stops to work - anvil problem

[FABIO FERRARI]

Hi all,

we have a problem about anvil, it seems that when we have a high load the
dovecot stops to work. Sometimes it is sufficient to make a dovecot
reload, but sometimes we have to restart it.

These are the lines related to anvil in the dovecot.log:

[root at secchia ~]# grep anvil /var/log/dovecot.log | more
Oct 26 11:13:55 anvil: Error: net_accept() failed: Too many open files
Oct 26 11:14:32 imap-login: Error: net_connect_unix(anvil) failed:
Resource temporarily unavailable
Oct 26 11:14:32 imap-login: Fatal: Couldn't connect to anvil
Oct 26 11:14:33 pop3-login: Error: net_connect_unix(anvil) failed:
Resource temporarily unavailable
Oct 26 11:14:33 pop3-login: Fatal: Couldn't connect to anvil
[...] (many lines like these)
Oct 26 12:01:10 pop3-login: Fatal: Couldn't connect to anvil
Oct 26 12:01:18 auth: Error: read(anvil-auth-penalty) failed: Connection
reset by peer
Oct 26 12:01:18 auth: Error: read(anvil-auth-penalty) failed: Connection
reset by peer
Oct 26 12:01:18 auth: Error: net_connect_unix(anvil-auth-penalty) failed:
Connection refused
Oct 26 12:01:18 auth: Error: net_connect_unix(anvil-auth-penalty) failed:
Connection refused
Oct 26 12:01:18 auth: Error: read(anvil-auth-penalty) failed: Connection
reset by peer
Oct 26 12:01:18 auth: Error: net_connect_unix(anvil-auth-penalty) failed:
Connection refused

And this is the output of the doveconf -n:

[root at secchia ~]# doveconf -n
# 2.0.1: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.18-308.11.1.el5 x86_64 Red Hat Enterprise Linux Server
release 5.8 (Tikanga) xfs
auth_cache_size = 1024
auth_cache_ttl = 21600 s
auth_debug = yes
auth_debug_passwords = yes
auth_master_user_separator = *
auth_mechanisms = plain login
auth_socket_path = /var/run/dovecot/auth-userdb
auth_verbose = yes
base_dir = /var/run/dovecot/
disable_plaintext_auth = no
hostname = mail.unimore.it
info_log_path = /var/log/dovecot.log
lda_mailbox_autocreate = yes
log_path = /var/log/dovecot.log
mail_debug = yes
mail_location = maildir:/cl/mail/vhosts/sms.unimo.it/%Ln/Maildir
mail_plugins = $mail_plugins quota
mailbox_idle_check_interval = 60 s
mbox_write_locks = fcntl
namespace {
  inbox = yes
  location =
  prefix = INBOX.
  separator = .
  type = private
}
passdb {
  args = /usr/local/etc/dovecot.masterusers
  driver = passwd-file
  master = yes
}
passdb {
  args = dovecot
  driver = pam
}
plugin {
  quota = maildir:User quota
  quota_exceeded_message = Quota exceeded (mailbox is full)
  quota_rule = *:storage=200MB
  quota_rule2 = *:messages=100000
  quota_rule3 = INBOX.Trash:storage=+100M
  quota_warning = storage=90%% quota-warning 90 %u
  quota_warning2 = storage=85%% quota-warning 85 %u
  quota_warning3 = messages=95%% quota-warning 95 %u
  quota_warning4 = messages=80%% quota-warning 80 %u
  setting_name = quota
}
postmaster_address = postmaster at unimore.it
quota_full_tempfail = yes
service anvil {
  client_limit = 199999
  process_limit = 199999
}
service auth {
  client_limit = 14500
  unix_listener auth-userdb {
    mode = 0600
    user = vmail
  }
}
service imap-login {
  inet_listener imap {
    port = 143
  }
  inet_listener imaps {
    port = 993
  }
  process_limit = 5000
}
service imap {
  process_limit = 5000
}
service pop3-login {
  inet_listener pop3 {
    port = 110
  }
  inet_listener pop3s {
    port = 995
  }
}
service pop3 {
  process_limit = 1024
}
service quota-warning {
  executable = script /usr/local/bin/quota-warning.sh
  unix_listener quota-warning {
    group = vmail
    user = vmail
  }
  user = dovecot
}
ssl_ca = </etc/pki/tls/certs/ca_unimore_tcs.pem
ssl_cert = </etc/pki/tls/certs/cert-852-mail.unimore.it-cluster.pem
ssl_key = </etc/pki/tls/certs/mailcluster.key
userdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
verbose_ssl = yes
protocol lda {
  mail_plugins = $mail_plugins quota
}
protocol imap {
  mail_plugins = $mail_plugins imap_quota
}
protocol pop3 {
  mail_plugins = $mail_plugins quota
  pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
  pop3_uidl_format = %08Xu%08Xv
}
[root at secchia ~]#

And these are the limit settings in the OS:
*               soft    nofile          131072
*               hard    nofile          131072

Have someone had the same problem?

thanks in advance

Fabio Ferrari