Understanding How to Transition to Exchange Server 2010

It is not required to completely restructure Exchange Server as part of the transition. In fact, if an Exchange Server 2003 or 2007 environment is working fine today, then just a simple transition is all that is required. The reason this book even addresses organizational restructuring as a potential option is that over the years with mergers, acquisitions, downsizing, or business changes, many organizations have Exchange Server structures that are not appropriate for the ongoing needs of an organization. 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 transition process more complex as are transitions that take place from a messaging system other than Exchange Server 2003/2007. Some of the transition changes are things that could take place before or after the transition to Exchange Server 2010.

Simple Transition from Exchange Server 2003 to Exchange Server 2010

For organizations that have a working Exchange Server 2003 environment that is happy with the architecture and operation of their Exchange Server environment and simply want to move to Exchange Server 2010, the transition process is a relatively simple and methodical process. In a condensed format, the process involves replacing Exchange Server 2003 front-end servers with Exchange Server 2010 Client Access Server (CAS) role systems, replacing bridgehead servers with Hub Transport (HT) servers, adding new Exchange Server 2010 mailbox servers, and moving the mailboxes from the old server, or servers, to the new server, or servers. It’s not quite that simple, however, 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 transition failure that requires rolling back during the transition process.

Restructuring Exchange Server as Part of the Transition to Exchange Server 2010

For organizations that have undergone business changes since the installation of Exchange Server, or that have an Exchange Server environment that is not architected properly for the current and near-future business environment of the organization, they might choose to restructure Exchange Server as part of their transition to Exchange Server 2010. The restructuring can occur with Exchange Server 2003 prior to the transition, the restructuring can occur during the Exchange Server 2010 transition, or the restructuring can occur after Exchange Server 2010 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 transition where, for example, several Exchange Server 2003 back-end servers are consolidated into a smaller number of Exchange Server 2010 mailbox servers. As mailboxes are moved from the old Exchange Server to the new Exchange Server, they can be moved from multiple systems to a single system. This restructuring is easy to do as part of the transition process.

Some transition 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 Server environment model. From an Exchange Server perspective, collapsing sites is one of the restructuring options that can be done as part of the transition; 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 transition that amount of mail over a WAN connection as part of a transition 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 transitioned in the data center. Although a logistical shuffle to physically move servers or data during the transition 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 Server transition. If the scope and goal of the transition is to do the restructuring in the Exchange Server transition project, plan the process and proceed with a restructuring of Exchange Server as part of the transition to Exchange Server 2010. 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 transition to Exchange Server, and then perform the restructuring after Exchange Server 2010 has been installed.

Transitioning to a Brand-New Exchange Server 2010 Organization

Another method for transitioning to Exchange Server 2010 is one where a brand-new Exchange Server 2010 server is built from scratch, and then data is moved into the new Exchange Server environment. An organization might choose to use this method if there are significant problems with their existing Exchange Server 2003 environment, or if the configuration of their existing Exchange Server environment is not ideally suited for Exchange Server 2010. This is a significant transition task and requires serious consideration regarding whether this is the best option. Instead, perhaps the Exchange Server 2003 environment can be cleaned up to a state where a simpler transition could take place. In nearly all scenarios, this is not a recommended option.

When building a new Exchange Server 2010 environment, data can be exported and imported from an old Exchange Server 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 Server configurations will need to completely rebuild their offline Outlook databases. Furthermore, in cases where the new Exchange Server 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 Server 2010, the organization will not be able to add back in an Exchange Server 2003 or Exchange Server 2007 system. Old Exchange server versions are only supported in an Exchange Server 2010 environment that was transitioned from the old version to the new version of Exchange Server. When Exchange Server 2010 is installed from scratch, none of the legacy backward-compatibility tools are installed or configured to work.

So, a brand-new Exchange Server 2010 installation is a drastic move for an organization that already has Exchange Server 2003. If the organization can do one of the transition methods and then clean up the model after transition, it would be easier to perform the transition.

Transitioning from Exchange Server 5.5 or Exchange 2000 Server

A transition from Exchange 5.5 or Exchange 2000 Server directly to Exchange Server 2010 is not supported and requires a transition first to Exchange Server 2003. After successfully transitioning to Exchange Server 2003, the organization can then execute the subsequent transition to Exchange Server 2010. For more information on performing a 5.5 to Exchange 2003 transition, refer to the SAMS Publishing book, Exchange Server 2003 Unleashed, Second Edition.

Migrating from Lotus Notes, Novell GroupWise, and Sendmail

The migration scenarios to Exchange Server involve an organization with an existing non-Exchange Server environment, such as Lotus Notes, Novell GroupWise, or Sendmail. The process of migrating from a non-Exchange Server environment is one that requires tools to transition user email, calendars, contacts, shared folders, and other information stored in the old email system to Exchange Server 2010. This type of migration usually starts with the installation of a completely clean Exchange Server 2010 environment in which user data is then migrated into the new environment. If Microsoft tools are used for these types of migration, they must be performed first to Exchange Server 2003 and then subsequently transitioned to Exchange Server 2010, as the Microsoft offerings for migrating from these platforms to Exchange Server 2010 are either weak or nonexistent. Many organizations look to third-party companies to fill this niche, or migrate first to Exchange Server 2003 before transitioning to Exchange Server 2010.

Transitions Involving a Limited Number of Servers

Beyond just transitioning from one version of messaging to Exchange Server 2010, the destination environment of Exchange Server 2010 can depend on the size and architectural structure of the resulting Exchange Server 2010 environment. For a small organization, the destination Exchange Server environment could be a single server where the various Exchange Server 2010 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 Server 2010 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 Server 2010 organization that host production data.

Transitions 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 Server 2010 server roles will replace the existing Exchange Server 2003 server systems with a similar distribution of server systems.

When transitioning to an Exchange Server 2010 environment with individual servers, the process of transitioning involves the following: