Migrating from Exchange 2007 to 2010, any general advice from the trenches?

Sure there are generic guides out there, but was just wondering if any actual day to day admins had any advice, tips, or gotchas to look out for, in order to, in the the safest and most effective way, migrate from our current single 2007 exchange virtual server to a new 2010 virtual server.  Helpful online resources, personal insights, or manuals appreciated.  Thanks in advance, folks.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

I just finished a 2007 to 2010 migration and ran into a few issues I didn't expect.  Here are some general tips plus the issues I ran into.

Upgrade the existing Exchange 2007 to the latest SP and rollups before you start.

Make sure your AD funtional levels are at least Windows Server 2003 forest and domain.

Make sure the all the end user clients can support EX 2010.  I'd recommend Office 2007 SP3 or later.

If you are using a SSL SAN certificate on the 2007 you might be able to get your SSL provider to add another couple of names to the existing certificate.  If you are using a wildcard certificate you can export that and use it on both the 2007 and 2010 CAS roles to support OWA and ActiveSync during the transition.

Build a 2007-2010 co-existence environment and migrate the users from 2007 to 2010 in batches.   If they are using Outlook they can send/receive mail during the mailbox move and get a message at the end of the move to restart Outlook.  Works well.  OWA users are not able to connect during the move.

If the co-existence environment is set up right, most smart phones will automatically move right over to the new case once the mailbox is moved.

Use Server 2008 R2 with EX 2010 for best results right now.  2012 has been giving people issues.

Unless you are putting in DAGs, you can and should use Windows Server 2008 R2 Standard Edition.  There is no reason to use enterprise unless you need more than 32 GB RAM which is a very big Exchange server.   If you are going to use DAGs, use the Enterprise Edition as it is needed for clustering.

Depending upon the number of users you are designing for you can use Exchange 2010 standard as the only difference is the number of databases you can use.   Use multiple databases and separate drives for databases and log files whenever possible.  1000 users is probably a good break point for going with Enterprise but not an absolute.  Remember Public Folders count as a database and so do passive DAG copies.  EX Std is limited to 5 databases.

I definitely favor putting in 2 Exchange 2010 servers for co-existence although not abosolutely necessary.  If you do one should be a CAS role and the other the HT and Mailbox server.   Follow the Microsoft design guides and use legacy.domain.tld for the 2007 CAS during migration and transfer the existing webmail.domain.tld or whatevery you currently use for OWA and Active Sync over to the new 2010 CAS.

AD domains that have been around for a while may have a problem with the security setting on the account.  Using ADUC, set the view to Advanced and look at the Security tab.  If the checkbox to propagate security via inheritance is not checked, that will give you a problem with ActiveSync when you move mailboxes from 2007 to 2010.

Another thing that may crop up is if the user account is or ever has been in the Domain Admins group.  A property is then set in AD called AdminCount=1.  this can give problems with Exchange 2010.  Best is to have all adminstrators use a separate admin account that is not mail enabled.  There are scripts on the Internet that you can use to set the security inheritance and clear the admin count for all Exchange users.  Even when a user is taken out of Domain Admins the value is not cleared.  

If you run into trouble with some smart phone users after migration, test their account using Microsoft's online Remote Connectivity Analyzer.  If the account generates errors it is not an ActiveSync problem or a phone problem but an account problem.

Of course, upgrade all your Exchange hook-in applications such as RightFax, BES, etc. and get them working before you migrate mailboxes.  

Test backing up and restoring mailboxes on the new server before migrating any accounts.

Apply all the latest patches, SPs, and update rollups to the Exchange 2010 server and OS before migrating any users.

If co-existence is set up right, all users will point to the new CAS server for ActiveSync, Outlook Anywhere, Autodiscover, and OWA before you start migrating mailboxes.  When users hit OWA or ActiveSync on the 2010 server it will know where their mailbox resides and automatically proxy them over to the 2007 CAS server.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
LB1234Author Commented:
Great write up Denver, thanks so much for the in depth info!!
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.