Migrating to Exchange Server 2007 : Understanding How to Migrate to Exchange Server 2007

It is not required to completely restructure Exchange as part of the migration. In fact, if Exchange 2000 or 2003 is working fine today, then just a simple migration is all that is required. Possibly, the organizational structure worked fine for years for the organization; however, a redesign is now needed because of a change in how the organization does business. These types of changes can make the migration process more complex as are migrations that take place from a messaging system other than Exchange 2000 or Exchange 2003. Some of the migration changes are things that could take place before or after the migration to Exchange 2007.

Simple Migration from Exchange 2000 Server and Exchange Server 2003 to Exchange Server 2007

For organizations that have a working Exchange 2000 or Exchange 2003 environment that is happy with the architecture and operation of their Exchange environment and simply want to move to Exchange 2007, the migration process is a relatively simple and methodical process. In a condensed format, the process involves replacing Exchange 2000 or Exchange 2003 front-end servers with Client Access servers, replacing bridgehead servers with Hub Transport servers, adding new Exchange 2007 Mailbox servers, and “dragging and dropping” the data from the old server, or servers, to the new server, or servers. It’s not quite that simple because there are several preparation steps that need to be conducted, a handful of test procedures that can assist the organization in the event of a migration failure that requires rolling back during the migration process.

Restructuring Exchange as Part of the Migration to Exchange Server 2007

For organizations that have undergone business changes since the installation of Exchange 2000 or 2003, or that have an Exchange environment that is not architected properly for the current and near future business environment of the organization, they might choose to restructure Exchange as part of their migration to Exchange 2007. The restructuring can occur with Exchange 2000 or 2003 prior to the migration, the restructuring can occur during the Exchange 2007 migration, or the restructuring can occur after Exchange 2007 has been put in place.

The deciding factor on when the restructure occurs depends on the effort involved to perform the restructuring. Some organizations will consolidate servers as part of their restructuring process. This is a simple process that can usually be done during the migration where, for example, several Exchange 2000 or 2003 back-end servers are consolidated into a single Exchange 2007 Mailbox server. As mailboxes are moved from the old Exchange to the new Exchange, they can be moved from multiple systems to a single system. This restructuring is easy to do as part of the migration process.

Some migration processes are more complex, for example, if the organization wants to completely collapse remote site servers and bring all of the servers into a centralized Exchange environment model. From an Exchange perspective, collapsing sites is one of the restructuring options that can be done as part of the migration; however, the challenge is typically trying to move large amounts of email over a wide area network (WAN) connection. If a remote site has several gigabytes or even tens or hundreds of gigabytes, it is unrealistic to migrate that amount of mail over a WAN connection as part of a migration process. In many cases, the actual server, hard drives of the server, or backup of the databases are physically brought into the centralized data center, and the data is migrated in the data center. Although a logistical shuffle to physically move servers or data during the migration process, this is not an insurmountable process than trying to move large sets of data across a slow WAN link connection.

The more complex restructuring model is required when an organization wants to add some sites, remove some sites, consolidate other sites, and completely redo sites that already exist. The choice of when to do the changes depends on the length and scope of the Exchange migration. If the scope and goal of the migration is to do the restructuring in the Exchange migration project, plan the process and proceed with a restructuring of Exchange as part of the migration to Exchange 2007. However, if the restructuring would be nice to have, but not significant to the scope of the project, you might choose to consolidate servers and migrate to Exchange, and then perform the restructuring after Exchange 2007 has been installed.

Migrating to a Brand-New Exchange Server 2007 Organization

Another method for migrating to Exchange 2007 is one where a brand-new Exchange 2007 server is built from scratch, and then data is moved into the new Exchange environment. An organization might choose to use this method if there are significant problems with their existing Exchange 2000 or 2003 environment, or if the configuration of their existing Exchange environment is not ideally suited for Exchange Server 2007. This is a significant migration task and requires serious consideration regarding whether this is the best option. Instead, perhaps the Exchange 2000 or 2003 environment can be cleaned up to a state where a simpler migration could take place.

When building a new Exchange 2007 environment, data can be exported and imported from an old Exchange environment to a new one; however, there will be many user interruptions and impacts. At a minimum, the Outlook profiles on user systems will need to be changed to point the user to a completely new Exchange server. Anyone with offline stores or cached-mode Exchange configurations will need to completely rebuild their offline Outlook databases. Furthermore, in cases where the new Exchange has a completely new organizational structure, links such as appointments or meeting requests will be disconnected from the person who invited them to the appointment because the new calendar might have different usernames, site configurations, and so on.

In addition, with a clean installation of Exchange 2007, the organization will not be able to add back in an Exchange 2000 or Exchange 2003 server. Old Exchange server versions are only supported in an Exchange 2007 environment that was migrated from the old version to the new version of Exchange. When Exchange 2007 is installed from scratch, none of the legacy backward-compatibility tools are installed or configured to work.

So, a brand-new Exchange 2007 installation is a drastic move for an organization that already has Exchange 2000 or 2003. If the organization can do one of the migration methods and then clean up the model after migration, it would be easier to perform the migration.

Migrating from Exchange Server 5.5

A migration from Exchange 5.5 to Exchange 2007 is not directly supported and requires a migration first from Exchange 5.5 to Exchange 2000 or from Exchange 5.5 to Exchange 2003. After successfully migrating to Exchange 2000 or Exchange 2003, the organization can then execute the migration to Exchange 2007.

Migrating from Lotus Notes, Novell GroupWise, and Sendmail

Yet another migration scenario is when an organization has an existing non-Exchange environment, such as Lotus Notes, Novell GroupWise, or sendmail.  The process of migrating from a non-Exchange environment is one that requires tools to migrate user email, calendars, contacts, shared folders, and other information stored in the old email system to Exchange 2007. This type of migration usually starts with the installation of a completely clean Exchange 2007 environment in which user data is then migrated into the new environment.

Migrations Involving a Limited Number of Servers

Beyond just migrating from one version of messaging to Exchange 2007, the destination environment of Exchange 2007 can depend on the size and architectural structure of the resulting Exchange 2007 environment. For a small organization, the destination Exchange environment could be a single server where the various Exchange 2007 roles are all on a single system. If there is no need to add additional server systems to the environment, then having a limited number of servers and placing server roles on a single system is easy to do.

The Hub Transport, Client Access, and Mailbox server roles of Exchange 2007 can all be placed on a single server; however, if the organization wants to add an Edge Transport server role to the organization, the Edge Transport server needs to be on a separate server. This is done for security purposes to isolate the Edge Transport server from other servers in the Exchange 2007 organization that host production data.

Migrations Involving a Distributed Server Strategy

For larger organizations, the various server roles will likely be applied to systems dedicated to a particular server role for purposes of performance and scalability. In many cases, a larger organization will already have existing roles for front-end and back-end servers, as well as bridgehead servers. In these larger environments, assuming that separate servers will be retained, the Exchange 2007 server roles will replace the existing Exchange 2000 and Exchange 2003 server systems with a similar distribution of server systems.

When migrating to an Exchange 2007 environment with individual servers, the process of migrating involves the following: