Migrating MS Exchange Server – what to be aware of


The word “Migration” changes its connotation. Nowadays, instead of bringing the image of caribou or wild geese traveling vast areas, it brings the image of moving data from one system to another. When the server administrator hears “Migration”, he usually thinks “Exchange”.

Exchange Server is one of (if not the most) important systems in today’s company. Without it the business operation stands still – no messages are sent or received, collaboration tools, such as Public Folders, are not working, chaos is growing. That is why system administrators are so cautious with any programmatic changes made on their servers. Each Microsoft update installation, each configuration change is performed with maximum caution to minimize the risk.

 “The more complex the system, the bigger chance of its failure and the harder way of fixing it”
– from Murphy’s law

One would think that Exchange migration is nothing more than copying mailboxes and users from one server to another. Well, it is far from it. The built in features of the Microsoft program make the process complex and multi-staged. E.g. migrating from Exchange 2003 to 2010 takes a number of steps, and each is quite a process all by its own:

  • Enable Exchange Native Mode for your exchange organization.
  • If not yet performed – install Service Pack 2 on all machines with Exchange 2003.
  • Raise the functional level of the AD forest/domains to Windows Server 2003.
  • On the machine that will contain Exchange 2010 install Windows Server 2008 R2 x64.
  • Install any necessary prerequisites (e.g. LDIFDE tools for schema upgrade).
  • Launch Exchange 2010 setup and upgrade the schema, prepare the forest and domains.
  • Install CAS server role.
  • Move traffic from OWA, ActiveSync etc. to new CAS server.
  • Hub Transport role installation.
  • Redirect all mail traffic to the new Hub Transport.
  • Install Mailbox server roles and configure Databases.
  • Prepare public folder structure on Exchange 2010 to accommodate current 2003 public folder structure.
  • Move mailboxes to the new Exchange Server 2010 using Powershell.
  • Designate Exchange Server 2010 as Offline Address Book base.
  • Designate Exchange Server 2010 as Public Folders base.
  • Transfer Public Folder to Exchange Server 2010.

Of course the above list is not the end of the story – administrator also has to plan how long the old 2003 setup is left as a backup structure, in case the new system fails, when and how to decommission the old server, what to do with 2003 databases backups etc.

Additionally, when moving between two different forests, the process is even more troublesome and requires enabling the trust between two structures, which is not always possible. Without the trust enabled the migration complicates significantly – the mailbox database has to be exported and imported as raw data. The export tool used for mailboxes does not work for public folders so they need to be moved via PST between Outlooks, which just adds the trouble. Moreover, all the permissions from 2003 are also lost, so they need rejiggering on the target system.

Since the 2013 version of Exchange Server is the latest, now many organizations are considering it as the migration target. However, the process for Exchange 2003 users is painful – it is called Staged Migration. Behind a nice name, it is nothing more than a two-step task: first migrate from 2003 to Exchange 2010. Then move from 2010 to 2013. Considering the list mentioned above the sheer amount of work required and the risks of servers going awry makes administrator want to migrate to some “happy place” without any computers in sight.

Luckily, there are solutions provided by third party companies that help to minimize the risk, straighten the process, and avoid any two-stage-because-MS-engineered-so scenarios.
CodeTwo Exchange Migration can transfer your mailboxes and public folders between different versions of Exchange, cross-forest and cross-domain wise and without Staged Migration when jumping from Exchange 2003 to Exchange 2013. Additionally there is also a 365 version of the program if the need to move to the cloud arises – check up on CodeTwo Office 365 Migration for more info.

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