Office 365 Migration Strategies – A Comparison

Different Office 365 migration methods have different benefits and drawbacks. Here are four key ones:

1. Manual Export and Import Migration

This simple method is good for organisations with few mailboxes.

Mailboxes are manually created in Office 365 with the correct email addresses, then mailboxes are exported to PST files and imported into Office 365 mailboxes.

Advantages

•    Simplicity – no Exchange Server changes.

Disadvantages

•    Manual method – mailboxes migrated singly – suitable for small numbers of user

•    The PST importer tool  can be unreliable

•    Exporting and importing with large mailboxes and a slow internet connection can be lengthy
•    Distribution groups and contacts are set up manually
•    Extra proxy addresses to each Office 365 Mailbox added manually
•    Replies to old internal emails don’t work automatically as the legacy exchange is missing
•    Permission to each mailbox is required to manually export mail to PST
•    New Outlook profile required for each user.

2. Cutover Migration

This is ideal if you can switch all users’ mailboxes to Office 365 in one night/weekend.  It involves configuring Office 365 to ‘pull’ all the mail from all the Exchange Mailboxes into Office 365 Mailboxes.  This process will then run daily to sync up the changes.  When you are ready to migrate to Office 365, the MX Records are changed, a final sync is done and Outlook users are manually set to use the new Office 365 Mailbox.

Advantages

•    All mailboxes, distribution lists and contacts synced up to Office 365 together
•    Correct proxy addresses added onto mailboxes
•    Legacy Exchange address added onto mailboxes for replies to old messages
•    Incremental sync runs daily to update mailboxes.

Disadvantages

•    New Outlook Profile required for each user
•    All in one switchover – extensive user support  needed
•    New cached .ost file must be downloaded for each mailbox.

3. Staged Migration

Staged exchange migration suits larger organisations or those wanting gradual migration to the cloud.  You can migrate some mailboxes to the cloud while keeping other mailboxes on site.

Advantages

•    Small numbers of mailboxes migrated together
•    All mailboxes, distribution lists and contacts synced up using Directory Sync Server
•    Correct proxy addresses added from Directory Sync Server
•    Legacy Exchange address added onto mailboxes for replying to old messages
•    Unified GAL between on-site and cloud
•    Mail routing between on-site and online.

Disadvantages

•    New Outlook profile required for each user
•    New cached .ost file downloaded for each mailbox
•    No free/busy information visible across platforms
•    Separate OWA for cloud users and on-site users.

4. Hybrid Migration

In a hybrid exchange, mailboxes reside on-site in an exchange organisation and the cloud. Messaging functionality is seamless across both deployments.  This long-term method causes minimal disruption.

Advantages

•    A small number of mailboxes is migrated at once
•    All mailboxes, distribution lists and contacts synced up using Directory Sync Server
•    Correct proxy addresses added onto mailboxes from Directory Sync Server
•    Legacy Exchange address added to mailboxes, allowing replies to old messages
•    Unified GAL between on-site and cloud
•    Mail routing between on-site and online
•    OST re-sync so no need to create separate Outlook profile or download old messages
•    Free/Busy and calendar sharing cross-premises
•    Out of Office understands cross-premises is “internal”
•    Outlook Web App redirection cross-premises (single Outlook Web App URL)
•    Can route outbound mail
•    Exchange Management Console (on-premises) used to manage cross-premises mailbox migrations
•    Mailbox moves support for on and off-boarding.

Disadvantages

•    Setup takes longer
•    On-site Exchange 2010 server required
•    ADFS required for single sign on – additional on-site servers required
•    Directory Sync Server required – and additional on-site servers.

If you need IT services, London has so many it can seem overwhelming. But Syntax’s extensive expertise makes it an ideal office 365 partner.