[Dovecot] performance?/connectivity? issues after server upgrade

[Udo Rader]

Hi,

we are facing some weird performance issues after we upgraded on of our
mail servers to a new Opteron 64bit machine.

The problem we are facing is that mail retrieval from external clients
is incredibly slow. Fetching a mail with say a size of 3MB takes 7
minutes vs. sending exactly the same mail back to our postmaster account
is only a question of seconds.

I've verified this with various customers and thus I am completely lost
here. The only service affected with this massive slowdown seems to be
dovecot but unfortunately I cannot think of a way to debug the issue ...

System load is absolutely minimal.

% dovecot -n
# 1.0.5: /etc/dovecot/dovecot.conf
log_path: /var/log/dovecot.log
protocols: imaps imap pop3
listen: 81.16.98.99
ssl_listen(default): 81.16.98.99
ssl_listen(imap): 81.16.98.99
ssl_listen(pop3): 
ssl_cert_file: /usr/bestsolution/ssl/certs/mail.bestsolution.at.pem
ssl_key_file: /usr/bestsolution/ssl/private/mail.bestsolution.at.pem
ssl_parameters_regenerate: 24
disable_plaintext_auth: yes
login_dir: /var/run/dovecot/login
login_executable(default): /usr/lib/dovecot/imap-login
login_executable(imap): /usr/lib/dovecot/imap-login
login_executable(pop3): /usr/lib/dovecot/pop3-login
first_valid_uid: 9
mail_extra_groups: mail
default_mail_env: mbox:~/mail/:INBOX=/var/mail/%u
mail_location: mbox:~/mail/:INBOX=/var/mail/%u
mmap_disable: yes
lock_method: dotlock
maildir_copy_with_hardlinks: yes
mail_executable(default): /usr/lib/dovecot/imap
mail_executable(imap): /usr/lib/dovecot/imap
mail_executable(pop3): /usr/lib/dovecot/pop3
mail_plugin_dir(default): /usr/lib/dovecot/modules/imap
mail_plugin_dir(imap): /usr/lib/dovecot/modules/imap
mail_plugin_dir(pop3): /usr/lib/dovecot/modules/pop3
pop3_uidl_format(default): 
pop3_uidl_format(imap): 
pop3_uidl_format(pop3): %v.%u
auth default:
  mechanisms: digest-md5 cram-md5 login
  passdb:
    driver: ldap
    args: /etc/dovecot/dovecot-ldap.conf
  userdb:
    driver: ldap
    args: /etc/dovecot/dovecot-ldap.conf
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/auth
      mode: 432
      user: postfix
      group: postfix

Any ideas welcome :-)

-- 
Udo Rader

bestsolution.at EDV Systemhaus GmbH
http://www.bestsolution.at
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