Server Migration - Moving up!

As we migrate all of our clients to a new email server, we've had the pleasure of dealing with lots of challenges in the middle of night. To prevent any disruption to users who are trying to send or receive email, we make all the changes when our clients are happily asleep.

Last night was the scheduled transition for our clients who leave their mail on the server and use webmail as their primary email interface. I had devised a rather simple plan based on the knowledge that the mail in the new server is all stored as simple text files -- not great for disk space, but easy to manage. My plan was to use a modified version of a POP3 reader that we use for automatically checking Non Delivery Report. The modified version would retrieve each email from a user's account and format it properly into a text file that could simply be dropped into the user's folder on the new server.

The modified version worked quite well and I started feeding it usernames and passwords to retrieve the client emails into individual folders to be ftp'd to the new server and all seemed to be going well...until I realized that there was a much simpler way to do this task. The new mail system allows you to configure POP retrieval accounts for individual users -- I was able to transfer mail between servers without any programming whatsoever simply by letting the new mail system do what it was designed to do.

The only trick that you need to know if you want to retrieve all of your email from an old system to a new one is that if an email has been read on the old system, some POP3 readers won't bother to get a copy of it. You can reset this by looking very technical and telnetting into the old mail server (port 110). By logging into each account that you need to migrate and giving it a "RSET" command, any indication that an email has been read will be removed and the new system will recognize it as unread mail and grab a copy for you.

The server migration is almost complete. It will be nice to have all the shared hosting / email easily accessible for quick changes and upgrades.

Side Note: The most devastating part of admitting to myself that the built-in system for retreiving the old email was that because the old and the new server are in the same datacentre, it took only a couple of minutes to transfer thousands of emails to the new box.