Migrating from Exchange to Google Apps

March 8, 2009 6:46 AM

Migrating from Exchange to Google Apps. Initially is it better to forward emails from Apps to Exchange, or the Exchange to Apps (before getting rid of Exchange altogether)?

I'm more interested in the reliability of the migration so that users do not experience interruptions and technical issues are minimised. I'm sure performance and security is the same either way.

I've had a look at the following but no luck:
Mefi: Transfer-Gmail-to-Google-Apps-Gmail
Google: guide-for-migrating-to-google-apps

Any other migration tips will be handy, as I read emails and contacts migration to Gmail can be a huge task...

Many thanks MeFi!

posted by gttommy to Computers & Internet (2 answers total)

Best answer: Since you're migrating away from Exchange toward Google Apps as your primary mail source, configure Google that way, and have it forward to Exchange (you may need to do this for each account). That way, Google is set up right away how it's going to be set up going forward, and you can shake out your issues while Exchange is still on. Otherwise, when you're ready to turn Exchange off, you will have to reconfigure Google Apps again into an untested state.
posted by mkultra at 7:12 AM on March 8, 2009

Best answer: If it's a Premium account, then IMAP is a great option for the actual migration. You get reports of errors and can just rerun any accounts if there are errors or to catch up on new emails. I migrated about 300,000 accounts to Google via IMAP and moved most of the mail in the week prior to the actual Go Live. Then identified the accounts that were active and re-migrated those after Go Live. We did some initial testing of the IMAP migration for performance testing purposes, but were able to go at a pretty good clip (obviously).

We elected not to run dual systems, except to the extent of keeping the old system running for the purposes of review and backup. This page from Google was the most helpful, including the Best Approaches for Large Migrations (pdf) document, which outlines switchover strategies (also a page here on that topic). The term that Google uses is Dual Delivery.

We did not migrate contacts. There is an API for that so it's technically possibly, but not particularly straightforward depending on your local expertise, etc. etc..
posted by idb at 7:43 AM on March 8, 2009