Email Migrations - Your guide to a successful email migration project.

When migrating from Exchange 2003 to Exchange 2007, there is a high probability that you receive a request to restore a mailbox from before the migration.

How do you do this ?   There are many ways you can retain some sort of Exchange 2003 infrastructure for restore purposes.   This could involve a lab setup, or leaving all your Exchange 2003 production mailbox servers in operation.

The most efficient solution I have found involves a little know trick using ADSIEdit and GUID swapping.  It will allow you to retain only one Exchange 2003 Server for your entire enterprise.  The assumption is that your production tape silo is not available for the lab, so you have to maintain the Exchange 2003 footprint in production to do those restores.

It is vital that you have kept a record of which Exchange 2003 Mail Store every user was on before the migration.  Use the CSVDE tool to achieve this via an export from Active Directory (be careful with this tool, and only do an export).

The trick is to run ADSIEdit  on the legacy Exchange 2003 Server and follow the below procedure to replace the msExchOrigMDB value on the RSG with the distinguishedName value on the Exchange 2007 Mailbox Store where the user mailbox currently resides.   Without doing this key step, ExMerge will not allow you to extract the mailbox contents to a PST, as it is expecting to find the user’s mailbox on the original legacy Mail Store.

Step 1:

After the mail migration, shrink down your Exchange 2003 environment so you have one of the mailbox servers left over.  Ensure it maintains access to suitable disk/SAN/tape drive.

Step 2:

Find out user’s current Exchange 2007 Mailbox Server, Storage Group and Mailbox Store

Find out user’s legacy Exchange 2003 Mailbox Server, Storage Group and Mailbox Store

On the Exchange 2003 Server create a Recovery Storage Group(RSG) that links to the legacy Exchange 2003 Mail Store that the user mailbox used to be homed on.

Prepare your backup media so you are ready for the restore.

Step 3:

Follow this procedure:

1. Start ADSI Edit.
2. Locate the mailbox store that you moved the mailbox to. To do so, expand Configuration Container [YourServerName.YourDomainName.YourTopLevelDomain], expand CN=Configuration,DC=YourDomainName,DC=YourTopLevelDomain, expand CN=Services, expand CN=Microsoft Exchange, expand CN=YourOrganizationName, expand CN=Administrative Groups, expand CN=Your Administrative Group, where Your Administrative Group is the administrative group that contains the storage group that you want to modify), expand CN=Servers, expand CN=YourServerName, expand CN=InformationStore, and then click CN=YourStorageGroup.
3. In the right pane, right-click the database object, and then click Properties.
4. In the Select which properties to view list, click Both.
5. In the Select a property to view list, click distinguishedName.
6. Right-click the value that is in the Value(s) box, and then click Copy.
7. Click Cancel.
8. Locate and then click the Recovery Storage Group database object in the CN=Configuration,DC=YourDomainName,DC=YourTopLevelDomain container.
9. In the right pane, right-click the Recovery Storage Group database object, and then click Properties.
10. In the Select which properties to view list, click Both.
11. In the Select a property to view list, click msExchOrigMDB.
12. Click Clear.
13. Right-click an empty area of the Edit Attributes box, and then click Paste.
14. Click Set, and then click OK.
15. Quit ADSI Edit.

Examples:

Example RSG msExchOrigMDB value before it is modified on Exchange 2003 Server

CN=StoreA,CN=SGA,CN=InformationStore,CN=2003SERVER,CN=Servers,CN=First Administrative Group,CN=Administrative Groups,CN=Exchange,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=contuso,DC=com

Example RSG msExchOrigMDB value after it is modified on Exchange 2003 Server

CN=StoreZ,CN=SGZ,CN=InformationStore,CN=2007SERVER,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=Exchange,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=contuso,DC=com

ExMerge:

Then use ExMerge to extract the mailbox required to a PST file.   Make sure the RSG is mounted.  The original Exchange 2003 mail store also needs to be mounted, even though the ADSIEDIT change was made earlier.  On the legacy Exchange 2003 server, make sure that the Mail Store containing the System Attendant Mailbox is also mounted.

Notes:

It will be possible to use the one Exchange 2003 Server to restore mailbox data that was originally homed on a different Exchange 2003 Server.  As long as your backup software allows you to restore to an RSG on a different server then Microsoft support this scenario.

I am just completing a major Exchange 2003 to Exchange 2007 migration.  All mailboxes and services have just completed migrating.  Exchange 2003 decom is now required – after remedial action is taken with Recipient Update Policies and Public Folders.