Installing Exchange Server 2010 into an existing Exchange Server 2007 environment (part 1) - Upgrading Active Directory

Before installing the first Exchange Server 2010 server into an existing Exchange Server 2007 environment, a number of prerequisites have to be met:

• All domains in an existing Active Directory forest have to be running in native mode.

• The Active Directory forest has to be running on a Windows Server 2003 forest functionality level.

• Each site in Active Directory should have at least one Domain Controller and the Global Catalog server on a Windows Server 2003 SP2 level. Although not enforced, it is recommended to have 64-bit type Domain Controllers and Global Catalog Servers for optimal performance.

• The Schema Master of the Active Directory needs to be a Windows Server 2003 SP2 or a Windows Server 2008 SP1 server. This can either be a 64-bit or a 32-bit server.

• All Exchange Server 2007 servers must have Service Pack 2 installed.

• The Internet facing Active Directory sites must be the first sites that will be upgraded to Exchange Server 2010.

Likewise, the physical server where Exchange Server will be installed needs to meet the following prerequisites:

• The server needs to be a 64-bit (64-bit, Itanium is not supported!) based computer.

• Windows Server 2008 SP2 or Windows Server 2008 R2 64-bit needs to be installed.

• Internet Information Server needs to be installed.

• Windows Remote Management (WinRM) 2.0 needs to be installed.

• PowerShell 2.0 needs to be installed.

• .NET Framework 3.51 needs to be installed.

Depending on the version of Windows 2008 you're using (i.e. Service Pack 2 or R2) a number of hotfixes need to be installed. I strongly recommend you bring your server up to date with the latest hotfixes from Windows Update.

1 Exchange Server 2010 order of installation

Exchange Server 2010 can be installed into an existing Exchange Server 2007 environment in the same forest and the same domain, but there are some issues with compatibility. You have to take the installation order of the Exchange Server 2010 servers into account to minimize the impact of this:

• First – Exchange Server 2010 Client Access Server. The Client Access Server can work with an Exchange Server 2007 Mailbox Server as well as an Exchange Server 2010 Mailbox Server.

• Second – Exchange Server 2010 Hub Transport Server.

• Third – Exchange Server 2010 Mailbox Server.

• The Edge Transport Server can be installed at any time, since an Exchange Server 2010 Edge Transport Server can be subscribed to an Exchange Server 2007 SP2 Hub Transport Server.

After you've installed the Mailbox Server role and established a proper Public Folder replication between Exchange Server 2007 and Exchange Server 2010, you can start moving mailboxes to the new Mailbox Server. Of course, the Public Folder replication needs only be configured when Public Folders are used in Exchange Server 2007.

Please bear in mind that an in-place upgrade to Exchange Server 2010 in any scenario is NOT supported!

2. Installing Exchange Server 2010

Although there's a specific order to the installation of server roles, these roles can, of course, be combined on one server.

When upgrading to Exchange Server 2010 the following steps need to be performed:

1. Upgrade the Active Directory Schema.

2. Upgrade the Active Directory Configuration.

3. Upgrade the Active Directory Domain.

4. Install the Exchange Server 2010 server roles.

So, let's get started with the upgrade.

2.1 Upgrading Active Directory

Before you even think about installing server roles, the first step in upgrading the Exchange Server 2007 environment to Exchange Server 2010 is upgrading the Active Directory Schema. Bear in mind that it is also possible to use the graphical setup program, as this can be found on the installation media as setup.exe. When you use this program, all steps below are automatically performed. The command prompt system is mainly for people who want to retain more fine-grained control over their transition.

This is not different from the procedure described in this article, and can also be achieved by entering the following into a command prompt:

Once the Schema has been upgraded, the Configuration (which is stored in the Active Directory Configuration Container) can follow.

Figure 1. The Exchange Organization in the Configuration Partition of a pure Exchange Server 2007 environment.

The Exchange Server 2007 organization called "RUBS" can be seen in Figure 15. All Exchange Server 2007 servers are stored in the default Administrative Group Exchange Administrative Group (FYDIBOHF23SPDLT). If your Exchange 2007 has previously been upgraded from Exchange Server 2003, then it's very likely that you will see a First Administrative Group as well. If the upgrade was finished correctly, this First Administrative Group should be empty, or almost empty.

Exchange Server 2010 also uses the Exchange Administrative Group (FYDIBOHF23SPDLT), but there are differences in how Exchange Server 2010 works, for example, with databases. In Exchange Server 2007, a database is bound to a Mailbox Server, while in Exchange Server 2010 databases exists on the organization level, independent of any Mailbox Server. So when upgrading the Exchange Configuration, the Administrative Group is changed to facilitate both the Exchange Server 2007 environment as well as the Exchange Server 2010 environment.

When you want to change the Exchange Configuration, open a Command Prompt, navigate to the Exchange Server 2010 installation media, and enter the following command:

After upgrading the Exchange Configuration, some Exchange Server 2010 specific entries appear in the Exchange Administrative Group, like the Database Availability Group and the Databases container. This is more or less what you should see:

Figure 2. The Configuration Container after upgrading the Active Directory. The Exchange Server 2010 specific entries are clearly visible.

The next step is to prepare the domain (or domains if you have multiple domains that host user accounts with Exchange Server mailboxes) for use with Exchange Server 2010. To do this, open a command prompt, navigate to the installation media and enter the following command:

And if you want to prepare all domains in your environment, enter the following command:

Figure 3. Preparing the current domain for Exchange Server 2010.

When the setup /PrepareDomain is finished, the Active Directory is now ready to install the first Exchange Server 2010 server.