migrate postfix accounts into google apps

Question

I have a postfix server (Linux) hosting a large amount of emails (120GB for 70 accounts) to be migrated into Google Apps. Only 30 accounts remain active and the remainder are archives.

What is an efficient way to migrate active accounts into Google Apps and minimize disruption? Are there scripts to read direct from the server disk then upload? What about folders and email statuses (read/flagged)?

Answer 1

Depending on the needs of your users, it's usually easier to cut over the MX records first and send your users to Apps for all new mail. Then, migrate over their old data. In this case, the downtime is very limited and they can always access the old server should they need something there.

The alternative would be to do multiple waves of migration that look something like:

1. Migrate all data from data X - Y
2. Change MX records for all users and send them to Apps
3. Run a second migration from date Y - Z to pick up any of the missed data (there won't be duplicates in emails if there's some overlap)

Regarding your last point, I'm guessing your users are using at least IMAP to access the mail server as I believe Postfix is not a mail server on its own. If this is the case, you'll want to use an IMAP migration for which Google provides a tool for (GAMME). An IMAP migration will bring over folder structure as well as read/unread status but I don't believe any 'flagged' status will translate.