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Re: Upgrade a mail server

Hello Craig 

On 19 Feb 2002, at 10:38, Craig Sanders wrote:

> i'd love to convert it over to Maildir/ but haven't yet found any way
> that doesn't involve many hours of downtime while converting the
> mailboxes from mbox format to Maildir.

I did this a while back. It is possible with very little apparent 
downtime.  (We are using Exim and Courier):

-   create Maildirs for all users.  (This is important if both your
    POP3/IMAP software and MDA are not configured to create missing
    Maildirs "on the fly"). 

-   change your MDA to deliver into the new maildirs 

(At this stage new mail is not visible to users when it arrives - but 
they can still see their old mail.  The downtime for this phase should 
be short)

-   change your POP3/IMAP programs to pick up mail from the

(At this stage old mail is not visible to users, but new mail is.  This 
should not be too much of a problem - if users have left MB worth of 
mail in their boxes, they can't want it too badly, it is when new mail 
is not available that people complain.)

-   run your script which reads the mbox files, and delivers to
    maildirs. My script renamed the mailbox files just after they
    had been converted, so I could restart the script without
    incurring duplicate deliveries if (when) the script crashed. 

-   By the time the script finishes, all mail is visible again. 

-   Keep the old mbox files around for a few days just in case you
    discover a problem ... 

No corruption, no duplication, no mail lost, no file locking, no error 
messages on client desktops, not too much loss of service and very 
few support calls.

Have fun!


Ian Forbes ZSD
Office: +27 21 683-1388  Fax: +27 21 674-1106
Snail Mail: P.O. Box 46827, Glosderry, 7702, South Africa

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