dovecot - Oct 2007 - performance?/connectivity? issues after server upgrade

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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On Fri, 2007-10-19 at 08:46 +0100, Ed W wrote:
> > 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
...
> >   
> 
> 
> Duplex mismatch on the network card?
grrrrrrrrrrrrrr, yes!!! Checking the link status of the NIC it showed
that indeed duplexing was giving wrong results. Forcing it into the
correct mode did not change anything, but finally replacing the card
with a new one solved the riddle!

Thanks for your help!

Udo Rader