timeouts when connecting to imap server

[Timo Veith]

Hi list readers,

I have a problem with our imap server. My users complain about timeouts 
when connecting to the server. We have nagios checking the status of the 
imap port. Most of the time it reports success and response times of less 
than one second. But sometimes the response takes longer than 10 seconds 
and then nagios reports a timeout. 

I don't think that the machine is overloaded, it's a dual xeon 2,8 ghz 
with 4 gb of ram and a gigabit link.

I am running Gentoo Linux with gentoo-sources as kernel (version 2.6.18), 
cyrus-imapd-2.2.12-r4 (autocreate patch applied). I have no iptables 
rules activated.

Because nagios just connects and disconnects right away, I don't think 
that the problem has something to do with authentication. However I am 
using saslauthd -> pam -> pam_ldap -> Active Directory. 

How can I find out what cyrus is doing right at the time when those 
timeouts happen or where the thing is hanging?

Thanks for reading and any tips and hints, config files are below.

Greetings,
Timo



Here is my /etc/cyrus.conf (IP address changed):

##############
# /etc/cyrus.conf
#
START {
  # Do not delete this entry!
  recover   cmd="ctl_cyrusdb -r"

  # This is only necessary if using idled for IMAP IDLE.
  idled     cmd="idled"
}

SERVICES {
  # Add or remove based on preferences.
  imap      cmd="imapd" listen="123.123.123.123:imap2" prefork=0
  imap      cmd="imapd -C /etc/imapd.conf.lo" listen="127.0.0.1:imap2" 
prefork=0

  pop3      cmd="pop3d" listen="123.123.123.123:pop-3" prefork=0
  pop3      cmd="pop3d -C /etc/pop3d.conf.lo" listen="127.0.0.1:pop-3" 
prefork=0

  # Don't forget to generate the needed keys for SSL or TLS
  # (see doc/html/install-configure.html).
  imaps     cmd="imapd -s" listen="123.123.123.123:imaps" prefork=0
  pop3s     cmd="pop3d -s" listen="123.123.123.123:pop3s" prefork=0

  sieve     cmd="timsieved" listen="123.123.123.123:sieve" prefork=0
  sieve     cmd="timsieved -C /etc/imapd.conf.lo" listen="127.0.0.1:sieve" 
prefork=0

  # at least one LMTP is required for delivery
  #lmtp     cmd="lmtpd" listen="lmtp" prefork=0
  lmtpunix  cmd="lmtpd" listen="/var/imap/socket/lmtp" prefork=0

  # this is only necessary if using notifications
  #notify   cmd="notifyd" listen="/var/imap/socket/notify" proto="udp" 
prefork=0
}

EVENTS {
  # This is required.
  checkpoint    cmd="ctl_cyrusdb -c" period=30

  # This is only necessary if using duplicate delivery suppression.
  delprune  cmd="ctl_deliver -E 3" period=1440

  # This is only necessary if caching TLS sessions.
  tlsprune  cmd="tls_prune" period=1440

  # create squat indexes for faster searches
  squatter cmd="squatter -r -s" at=0400
}
#
########## end of /etc/cyrus.conf


And here is my /etc/imapd.conf:

#############
# /etc/imapd.conf
#

# when you change these directories (read the docs).
configdirectory:    /var/imap
partition-default:  /var/spool/imap
sievedir:       /var/imap/sieve

tls_ca_file:        /etc/ssl/cacert.pem
tls_cert_file:      /etc/ssl/crt.pem
tls_key_file:       /etc/ssl/key.pem

hashimapspool:      yes
allowanonymouslogin:    no
# only on localhost /etc/imapd.conf{,.lo}
allowplaintext:     no

autocreatequota: 102400

createonpost: yes

sasl_mech_list:     LOGIN PLAIN

unixhierarchysep: 1

lmtp_downcase_rcpt: 1

# auxprop only on localhost /etc/imapd.conf{,.lo}
#sasl_pwcheck_method:   saslauthd auxprop
sasl_pwcheck_method:    saslauthd
#sasl_auxprop_plugin:   sasldb

allowapop: 0
#
######## end of /etc/imapd.conf