On Jun 29, 2007, at 2:00 AM, Robert Schetterer wrote:

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Dehnert James Sr schrieb:

...

I have a client that I have installed Dovecot 1.0.1 for is having
some performance issues. Especially when using IMAP from various Outlook clients. I have TLS installed and all the IMAP connections are
secured.

I'm wondering is anyone has any recommendations for monitoring
dovecot performance. I'd like to try and nail down where the real
performance issues are. I suspect outlook, but I want to eliminate Dovecot as
the cause of any problems, or, if I have a problem with Dovecot, I
want to identify any issues I can and fix them.

Thanks, Zeke

-- James "Zeke" Dehnert mailto:jdehnert@norcalnetworks.com Phone: +1 707.546.6620 x602 Fax: +1 707.324.8043 "Life is racing, everything else is just waiting"

Hi, outlook isnt outlook , first clear what versions they use each version of outlook is different ( including their service pack
levels ) so i.e. outlook 2007 makes imap stuff very different to the versions before, after all outlook wasnt a very good imap client since ever. Be sure that you have recommanded Outlook entries in dovecot.conf
( see wiki )

The client has basically every combination of Outlook and Outlook
Express imaginable.

and if you need help you should show your dovecot.conf here.

Dovecot.conf

protocols= imap imaps pop3 pop3s protocol imap { listen = 127.0.0.1 ssl_listen = * } protocol pop3 { listen = 127.0.0.1 ssl_listen = * } disable_plaintext_auth = yes log_path = /var/log/dovecot/dovecot.log info_log_path = /var/log/dovecot/dovecot.log log_timestamp = "%b %d %H:%M:%S " ssl_disable = no ssl_cert_file = /etc/postfix/certs/mail_public_cert.pem ssl_key_file = /etc/postfix/certs/mail_private_key.pem ssl_ca_file = /etc/postfix/certs/cacert.pem ssl_cipher_list = ALL:!LOW verbose_ssl = no login_greeting = Dovecot ready. mail_location = maildir:/var/spool/mail/%u/ mail_debug = no lock_method = fcntl verbose_proctitle = yes first_valid_uid = 500 mbox_read_locks = fcntl protocol imap { imap_client_workarounds = outlook-idle delay-newmail } protocol pop3 { pop3_uidl_format = %08Xu%08Xv pop3_client_workarounds = outlook-no-nuls } protocol lda { postmaster_address = postmaster@client.com } auth_verbose = no auth_debug = no auth_debug_passwords = no auth default { mechanisms = plain login passdb pam { } userdb passwd { } user = root socket listen { client { path = /var/spool/postfix/private/auth mode = 0660 user = postfix group = postfix } } }

and describe what perfomance stuff you mean, have you tested it by
your own ( dont trust users ! )?

The performance issues are a) slow response on the lan, and b)
unusable low response from remote users. This is always with IMAP,
of we switch the users to POP3 things are acceptably fast. With POP3
things are just plain snappy performance wise. With IMAP there are
noticeable waits for messages to appear. The field users are of
particular concern. They can see message headers, but they never get
the message bodies downloaded. I have checked their configurations,
and with the same systems connected locally that can get to all of
their mail. I realize there are a number of factors that could
affect a remote user that are out of my control, but I can connect
remotely with my Mac (mail.app) and the performance seems fine to me.

For a first look you should have a i.e dovecot.log etc to see failures

I have been prowling the logs for weeks, there are no errors that I
can correlate to IMAP performance (no errors at all really, just the
standard connect-disconnect messages), which is why I'm looking for
recommendations for performance monitoring. I have ratcheted up the
debugging on the log files, but all I see is more info on normal
behavior.

I believe that Dovecot is running just fine, but I need some metrics
to prove that to the users.

I think i remember reading problems with outlook 2007 and tls, but
i can remember exactly

I have no reports from users having problems with outlook and dovecot 1.0.1 at my systems ( but i dont think i have much of them, so i cant say that problems are are unthinkable *g ) )

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Mit freundlichen Gruessen Best Regards

Robert Schetterer

https://www.schetterer.org Germany -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org

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Thanks, Zeke

-- James "Zeke" Dehnert mailto:jdehnert@norcalnetworks.com Phone: +1 707.546.6620 x602 Fax: +1 707.324.8043 "Life is racing, everything else is just waiting"

On Fri, 2007-06-29 at 10:45 -0700, Dehnert James Sr wrote:

I believe that Dovecot is running just fine, but I need some metrics
to prove that to the users.

You could for example patch rawlog to log timestamps before each input/output packet so you can see how long it takes for Dovecot to reply to commands. If most of the time is spent waiting for incoming commands then the problem isn't with Dovecot.

Attached a patch (untested though), and http://dovecot.org/bugreport.html#sniffing explains how to enable rawlog.

If the problem isn't with Dovecot, maybe your users have some software firewall on the way that slows everything down.