Deep understanding on O365 Exchange Migration – Interview Questions with explainations

While migrating the on premises exchange from your existing environment to O365 Exchange, below are list of queries you may come across : Q1: What are migration options available when migrating to O365 ?

 There are 4 specific Migration options –  (1) iMAP, (2) cutover, (3) staged (4) hybrid They are Remote move migrations, Staged Exchange migrations, Cutover Exchange migrations and IMAP migrations. You can find the details in Mailbox migration to Exchange Online.

Q2: What’s the benefit of using a hybrid type over the other migration types?

 A hybrid deployment offers organizations the ability to extend the feature-rich experience and administrative control they have with their existing on-premises Microsoft Exchange organization to the cloud. A hybrid deployment provides the seamless look and feel of a single Exchange organization between an on-premises Exchange Server 2013 organization and Exchange Online in Microsoft Office 365. In addition, a hybrid deployment can serve as an intermediate step to move completely to an Exchange Online organization.

Q3: Do you know what DirSync is? What is it used for?

 A3: DirSync, as known as the Azure Active Directory Sync tool, synchronizes your on-premises Active Directory users to Office 365. For details, I suggest you refer to: Plan for directory synchronization for Office 365.

Q4: Which of the 4 migration methods would use DirSync?

 Hybrid and staged migration will need installation of DirSync before the migration. We can’t perform a cutover migration if DirSync is deployed.

Q5:  If you are in a hybrid environment and want to create a new mailbox – how and where would you do that?

 A5: Create the mailbox in the on-premises mailbox, then move it to Office 365 using the move request. For details, please refer to: Move Mailboxes Between On-Premises and Exchange Online Organizations in 2013 Hybrid Deployments.

Q6: How will the user know if their mailbox has been moved to the cloud?

 In a hybrid deployment, once we have the Hybrid setup in place, and then Migrate that particular users mailbox to the cloud, exchange will push an update of those settings to that user. The user will get a notification ‘the administrator has updated your settings and you must restart outlook’. Once Outlook restarts, their RPC/HTTP settings will point to Office 365 automatically.

Q7: How does the mail client know where to send mail once the mailbox has been moved to the cloud?

 In a hybrid deployment, once the user is migrated, the migration will set a TargetAddress attribute to the on-premises user. The message will be delivered to Office 365 based on the attribute.

Q8: How do you troubleshoot connection issues with for a new user with a remote mailbox?

For how to troubleshoot the Outlook connectivity issue for an Exchange Online mailbox, please refer to: Fix email connectivity problems after Office 365 upgrade.

Q9: How can you troubleshoot availability (free/busy) failures from cloud mailboxes to on-premises mailboxes?

 You can refer to this article: How to troubleshoot free/busy issues in a hybrid deployment of on-premises Exchange Server and Exchange Online in Office 365 to troubleshoot the issue.

Deciding Matrix to choose Migration Type :

Use the following table to decide what type of migration works for your organization.

Existing organization Number of mailboxes to migrate Do you want to manage user accounts in your on-premises organization? Migration type
Exchange 2013, Exchange 2010, Exchange 2007, or Exchange 2003 Less than 2,000 mailboxes No Cutover Exchange migration
Exchange 2007 or Exchange 2003 Less than 2,000 mailboxes No Staged Exchange migration
Exchange 2007 or Exchange 2003 More than 2,000 mailboxes Yes Staged Exchange migration or remote move migration in an Exchange hybrid deployment
Exchange 2013 or Exchange 2010 More than 2,000 mailboxes Yes Remote move migration in an Exchange hybrid deployment
Exchange 2000 Server or earlier versions No maximum Yes IMAP migration
Non-Exchange on-premises messaging system No maximum Yes IMAP migration