                Cyrus IMAP Server FAQ

      * Using PAM Under Linux when using PAM and shadow passwords,
        /etc/shadow needs to be readable by the Cyrus user. 
      * Using NFS We don't recommend it. If you want to do it, it may
        possibly work but you may also lose your email or have corrupted
        cyrus.* files. You can look at the mailing list archives for more
        information. 
      * Virtual hosting - We don't support it and don't plan to support it
        unless we get a set of complete patches. If you want it, you'll
        need to do it yourself or use a commercial product. Check the list
        archives for more information. 
      * dots in userids - no you can't have a '.' in your username. 
      * Performance/Capacity/Scaling - There is no good answer for this. It
        depends on your hardware, your operating system, and how your users
        use the system. In general, an imapd process takes up anywhere from
        256 Kbytes of memory to 512 Kbytes when it is first fired up. CPU
        has not been a big deal, but it may become more important as the
        imap sessions are encrypted and now that searching may be more
        frequent. Disk I/O is probably the most important and having a
        hardware RAID subsystem with an amount of write-back cache would be
        a good thing. 

        Finally, if you are talking about less than 100 interactive users
        it is likely that any relatively modern hardware can support it. If
        you are talking about having more than 1000 interactive users, you
        should know how to predict your utilization, go overboard on
        hardware, be willing to suffer growing pains, or be able to hire
        someone that can help. 

        There are a number of good performance tuning articles out for
        Solaris by Adrian Cockcroft. Go to your favorite search engine and
        look for his name. 

Troubleshooting

    Q: I'm getting syslog'd messages from the master process saying
            processes are "signaled to death by 10". What's up? 
            

            A: Try installing some patches to Berkeley DB available from
            http://www.sleepycat.com/update/3.0.55/patch.3.0.55.html. 
    Q: I've used saslpasswd to create CRAM-MD5 secrets, but imapd doesn't
            say AUTH=CRAM-MD5. Why? 
            

            A: Make sure /etc/sasldb is readable by the Cyrus user. 

