[Dovecot] vsz_limit

Wed Feb 8 10:58:30 EET 2012

Hello Timo and dovecot teamwork,

We have dovecot 2.0.10 installed with this configuration:

# dovecot -n
# 2.0.10: /usr/local/dovecot/etc/dovecot/dovecot.conf
# OS: Linux 2.6.18-92.1.18.el5 x86_64 Scientific Linux SL release 5.2 (Boron)
auth_cache_size = 500 k
auth_cache_ttl = 1000 secs
disable_plaintext_auth = no
first_valid_uid = 501
lock_method = dotlock
mail_fsync = always
mail_gid = vmail
mail_location = maildir:%h/Maildir
mail_nfs_index = yes
mail_nfs_storage = yes
mail_plugins = quota autocreate
mail_uid = vmail
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
mmap_disable = yes
namespace {
  inbox = yes
  location =
  prefix =
  separator = .
  type = private
}
namespace {
  hidden = yes
  inbox = no
  list = no
  location =
  prefix = INBOX.
  separator = .
  type = private
}
namespace {
  location = maildir:%h/Maildir/_backup
  prefix = _backup.
  separator = .
  type = private
}
passdb {
  args = /etc/dovecot/dovecot-ldap.conf
  driver = ldap
}
plugin/autocreate = Spam
plugin/autosubscribe = Spam
plugin/quota = maildir:_backup:ns=
plugin/quota_warning = storage=75%% quota-warning 75 %u
plugin/quota_warning2 = storage=90%% quota-warning 90 %u
plugin/sieve = %h/.dovecot.sieve
plugin/sieve_dir = %h/sieve
protocols = imap pop3 sieve
service anvil {
  client_limit = 5000
}
service auth {
  client_limit = 9000
  unix_listener auth-master {
    group = vmail
    mode = 0700
    user = vmail
  }
  user = root
  vsz_limit = 2 G
}
service imap-login {
  executable = /usr/local/dovecot/libexec/dovecot/imap-login
  inet_listener imap {
    address = *
    port = 143
  }
  inet_listener imaps {
    address = *
    port = 993
  }
  process_limit = 2048
  process_min_avail = 20
  user = vmail
}
service imap {
  executable = /usr/local/dovecot/libexec/dovecot/imap
  process_limit = 2048
}
service managesieve-login {
  executable = /usr/local/dovecot/libexec/dovecot/managesieve-login
  inet_listener sieve {
    address = *
    port = 4190
  }
  inet_listener sieve_deprecated {
    address = *
    port = 12000
  }
  user = vmail
}
service managesieve {
  executable = /usr/local/dovecot/libexec/dovecot/managesieve
}
service pop3-login {
  executable = /usr/local/dovecot/libexec/dovecot/pop3-login
  inet_listener pop3 {
    address = *
    port = 110
  }
  inet_listener pop3s {
    address = *
    port = 995
  }
  process_limit = 2048
  process_min_avail = 20
  user = vmail
}
service pop3 {
  executable = /usr/local/dovecot/libexec/dovecot/pop3
  process_limit = 2048
}
service quota-warning {
  executable = script /usr/local/dovecot/bin/quota-warning.sh
  unix_listener quota-warning {
    group = vmail
    mode = 0700
    user = vmail
  }
}
ssl_cert = </etc/ssl/correo_xxxx.crt
ssl_key = </etc/ssl/correo_xxxx.pem
syslog_facility = local3
userdb {
  args = /etc/dovecot/dovecot-ldap.conf
  driver = ldap
}
valid_chroot_dirs = /buzones/
protocol imap {
  imap_client_workarounds =
  mail_plugin_dir = /usr/local/dovecot/lib/dovecot
  mail_plugins = quota autocreate imap_quota
}
protocol pop3 {
  mail_plugin_dir = /usr/local/dovecot/lib/dovecot
  mail_plugins = quota autocreate
  pop3_uidl_format = %08Xu%08Xv
}
protocol lda {
  auth_socket_path = /usr/local/dovecot/var/run/dovecot/auth-master
  hostname = buzon.xxxx.es
  mail_plugin_dir = /usr/local/dovecot/lib/dovecot
  mail_plugins = quota autocreate sieve
  postmaster_address = postmaster at xxxx.es
  quota_full_tempfail = no
  rejection_reason = Su mensaje para <%t> fue rechazado automaticamente por nuestro sistema :%n%r
  rejection_subject = Rechazado: %s
  sendmail_path = /usr/sbin/exim
}
protocol sieve {
  managesieve_implementation_string = dovecot Pigeonhole
  managesieve_logout_format = bytes ( in=%i : out=%o )
  managesieve_max_line_length = 65536
}

The problem is at the moment of maximum load of the system. We can see many imap sessions but there are also many imap-login processes, which is weird. Has it something to do with any parameter of our configuration? We think is something with the vsz_limit parameter. How can we tune it?

Thank you very much in advanced.

Kind regards.

________________________________
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Héctor Moreno Blanco
División de Seguridad e Infraestructuras /
Security and Infrastructures Division

GMV
Isaac Newton, 11
P.T.M. Tres Cantos
E-28760 Madrid
Tel. +34 91 807 21 00
Fax +34 91 807 21 99
www.gmv.com <http://www.gmv.com/>
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