Migrate QMail to Cyrus

Matthew Schumacher matt.s at aptalaska.net
Thu Jul 20 13:49:33 EDT 2006

Patrick T. Tsang wrote:
> Read this link, and then you know why mailutil is NOT good enough.
> http://www.webservertalk.com/message1280487-1.html
> I am also having this problem.
> To improve the speed, I have to tar the mail to the new server and do
> reconstruct, and then use imapsync to re-build the imap flag and
> re-subscrib the imap folder.
> However, I am still not satisfied by this method.
> Please kindly share me a better way.
> BTW, people using SAN for clustering solution is welcome, too.
> Patrick

When We did this we needed to loop though our ldap database so I wrote a
perl script that read the uw-imap mbox files and copied them to cyrus
via imap.  I found that it was slow so I rewrote it to spool a new child
for each mbox file, with 10 threads running at a time.  This made it
much faster, but it still wasn't that fast.  After some tweaking I got
it to go at a reasonable speed, but at some point I think I was hardware
bound.  My script didn't block up the messages so consumed a ton of
memory (which was recovered when each child died) however it did work.

I used up every minute of my maintenance window to get it moved, but it
did work and there where minimal issues the following day.

If I had a bigger site, I would probably use some form of imap proxy to
aggregate imap traffic to the old and new server while I migrated a
couple thousand accounts at a time.

In the end mail migrations are a pain, but cyrus is worth it.
Performance and features are better than any other imap server I have
found.  Add this to mimedefang/sendmail and you have a very good mail


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