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A transition to Office 365 is disruptive to a business for good and bad reasons. A successful migration enhances...
productivity, whereas a troublesome migration causes pain for end users and potentially even leads to lost revenue for a business.
Office 365 comprises a number of integrated platforms: Exchange Online, SharePoint Online, OneDrive for Business, Skype for Business Online, Office Pro Plus and Yammer. You should consume all -- or at least most -- of these services to make the investment worthwhile, and that's not a simple switch.
Most organizations start with Exchange Online and migrate email to the cloud first. This is often done in conjunction with a rollout of the new Office Pro Plus client. By starting the migration with this core business system moving to the cloud, the business sees an early ROI often with minimal interruption to users.
When creating your adoption plan for the transition to Office 365, be sure senior executives understand and support the overarching goal. Users also need to be in the loop. Aim for a series of workshops, all-company meetings and regular, friendly communication. If there are desk visits or a small degree of disruption, informed users will be more accommodating.
A successful migration requires a thorough understanding of the current environment. With Office 365, this process means gathering information about the number of employees at each site, where specific departments are located within the organization, network links between sites, and existing firewall and supporting proxy server infrastructure.
Identity forms the core of the relationship between the source environment and Office 365. Azure Active Directory, Office 365's underlying identity service, will have a copy of on-premises Active Directory accounts. Carefully examine information about security requirements, such as if multi-factor authentication is needed for external access to email.
The User Principal Name (UPN), or the Windows 2000 Account Name in Active Directory, is usually copied to Office 365 and instituted as the login ID. Alternate Login ID is not typically suitable for email migrations. Therefore, you will need to update UPNs to use a valid Internet-routable domain name system suffix. The most appropriate option is usually to make the UPN match the email address.
Catalog which objects you want to sync -- this decision should be made based on the organizational unit and the total sync count. Use Microsoft's IdFix tool to identify any errors within the synching data. The tool is provided in the Office 365 portal.
For a mail migration and a smooth transition to Office 365, you must assess the email environment. In particular, inventory the current Exchange (or third-party) versions and the corresponding patch level. You should know how Exchange Server is published to the Internet and if valid SSL certificates or pre-authentication are used. All in-use, accepted domains will need to be registered within the Office 365 tenant.
Check the number of mailboxes in use, including shared mailboxes, for license assessment and migration planning. Estimating how long a migration will take becomes clearer once you know the mailbox size and item counts.
If your organization uses many public folders, then you must determine whether you can migrate to another platform, such as SharePoint. Another option may be to move the functions to shared mailboxes. Public folder coexistence is available but ideally avoided.
Third-party systems are often the Achilles heel of mail migrations because they may need to be upgraded to their latest versions either before or after a migration to ensure success. These include unified messaging integration with an IP PBX, antispam systems, journaling and archive systems, fax software, signature software or client-side add-ins.
Client versions are equally important. As of early 2015, a fully patched Office 2007 client was the practical bare minimum for connection to Office 365. A fully patched copy of Office 2010 works well and Office 2013 or higher provides the best experience and all new features.
You will also need to know the mobile estate that's in use within the organization, including ActiveSync clients and mobile device management products. Mobile devices often need reconfiguration -- and possibly replacement -- to continue working post migration.
Deciding on the best approach
The two best migration approaches are using hybrid technologies or relying on a third-party migration tool. The other Exchange options, staged and cutover, are only suitable for smaller organizations. Internet Message Access Protocol (IMAP) works, but it is very limited unless you run a simple open source mailer.
A hybrid migration effectively extends the on-premises Exchange organization into Office 365. This enables secure mail flow, native sharing and full-fidelity mailbox moves, the latter of which allows the pre-staging of data, automatic client reconfiguration and retention of the offline cache. A hybrid migration requires the most preparation, but for larger or complicated organizations it has the biggest payoff. Hybrid works with Exchange 2010 and 2013, and a hybrid "bridge" server can be installed into Exchange 2003 and 2007 environments.
A third-party transition to Office 365 using products such as BitTitan's MigrationWiz, Binary Tree's E2E Complete, and Refresh IT Solutions' tools is the best experience for organizations that do not have the time to implement -- or cannot implement -- a hybrid migration. These tools provide similar pre-staging technologies and in some cases accelerate the process by migrating recent data first and then legacy data after the user switches to Office 365. These tools usually include client reconfiguration and automation technologies. Third-party tools work with all common Exchange versions and a wide range of third-party mail servers like Lotus Notes or Google Mail.
Cutover migrations work for smaller companies, as directory sync is available and the entire organization is switched in a single operation. On the day of the move, every client must be visited and reconfigured, and all users provided a new password with which to access Office 365. Cutover works with Exchange 2003 to 2013.
A staged migration -- another good choice for small organizations -- makes use of the same directory sync technologies used in a hybrid migration, but copies data with the external connection feature Outlook Anywhere. A staged migration is a one-shot migration per user. After each batch, single users are visited and the client is reconfigured.
IMAP migrations are great for open source mail servers, such as UW-IMAPD, Dovecot and other similar systems that provide a rudimentary experience. Like staged migrations, the IMAP migration creates a batch and copies mail in a single run. When a third-party tool is not available, IMAP can be used to migrate mail from other third-party systems that support the technology, such as Lotus Notes.
If you're using a third-party archiving or journal system like Symantec Enterprise Vault, then a third-party archive migration tool is often required. Archive migration tools from companies including BitTitan, Transvault, SimplyMigrate, Archive360 and QuadroTech take some of the pain out of extracting data from the source archive and loading it into Office 365. In addition, these tools often clean up "short cut" stub data to ensure the mailbox is clean and functional for the user.
About the author:
Steve Goodman is an Exchange MVP and is the head of unified communications at the U.K.'s leading Office 365 partner. Steve has worked in the IT industry for 16 years and has worked extensively with Microsoft Exchange since version 5.5. Steve is the author of a number of books about Exchange, regularly presents at conferences, co-hosts The UC Architects podcast and regularly blogs about Exchange Server, Office 365 and PowerShell at www.stevieg.org.
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