IMAP/LMTP delays (was Re: IMAPD Mail Delays)

From: Michael D. Sofka (no email)
Date: Wed Sep 05 2007 - 15:16:45 EDT

  • Next message: Ken Murchison: "Re: ...and a question (SHA1 UUIDs)"

    On Tuesday 04 September 2007 03:42:05 pm Corey Bobb wrote:
    > The current problem I am having is that I am receiving mail from my outside
    > email relay (postfix) which From what I gather forwards it over the cyrus
    > mail sever however, I can see the postfix server getting the mail . ..but
    > it will take another 30 minutes before the message can actually be viewed
    > in a mail client.

    I've been seeing this as well. In our case, it's cyrus 2.2.12 with
    sendmail 8.13.1 using MAILER(cyrus2). Cyrus is run in a murder cluster with a
    master, two front-end and three back-end servers (one not in use---old, being
    retired, running account creation scripts which need to be moved).

    Sendmail reports: "Deferred: Connection timed out with mail.rpi.edu."
    And, occasionally it reports: "Deferred: Broken pipe." (mail.rpi.edu is a
    vip. Port 25 connections are sent to one of four smtp machines via a Cisco
    CSS director.)

    The 60 minute delay (in our case) was due to the MinQueueAge parameter in
    sendmail. Once email was deferred to one of the smtp servers, that server
    continued to queue email for 15 minutes (when the .hoststat is rechecked).

    The queue runners would skip the queued email for 1 hour. To patch this, I
    put the local email in a separate queue group, and run sendmail out of cron
    with MinQueueAge value of 10 minutes. (Putting a runner on the queue group
    didn't work, since MinQueueAge takes precedence.)

    But, the base problem remains: For some reason lmtp is returning a 400-level
    dsn.

    Perhaps related, or not, I have also noticed occasional delays connecting to
    IMAP. They tend to cluster around 15 minutes before the hour. It got
    particularly bad when students returned last week.

    Google turned up a mention of an error in mupdate which caused it to double
    free threads when the maximum connections is reached. Indeed, there were
    numerous "could not start a new worker thread" errors in the cyrus.log file on
    the murder master. I doubled mupdate_connections_max to 2048 and the
    problem is reduced. The delays are still there, but they do not last as long.
    There are still a few 'could not start worker thread' errors. The process
    involved restarting services on the master, which killed about 800 mupdate
    connections. Currently there are about 26 mupdate connections.

    Any help with this (these?) problem(s) appreciated.

    Mike

    -- 
    Michael D. Sofka               
    C&MT Sr. Systems Programmer,   Email, TeX, Epistemology
    Rensselaer Polytechnic Institute, Troy, NY.  http://www.rpi.edu/~sofkam/
    ----
    Cyrus Home Page: http://cyrusimap.web.cmu.edu/
    Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki
    List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
    

  • Next message: Ken Murchison: "Re: ...and a question (SHA1 UUIDs)"





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