Office 365 Migration Types – What is the Best for Me?

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Blog | Mar 27, 2017

Office 365 Migration Types – What is the Best for Me?

TriCore Solutions can migrate emails from various email systems to Office 365. Each migration method has its own pros and cons, however the impact can always be minimized with a pre-assessment of the source email environment and a proper migration strategy.

Introduction: - TriCore Solutions can migrate emails from various email systems to Office 365, there are a variety of migration methods that can be used depending on the customer requirements. Factors you should consider when making the choice of a migration method include:

  • Number of objects to be migrated
  • Amount of data to be migrated
  • Existing email system
  • Exchange Servers version
  • Time duration of the migration project
  • Costs involved

It is important to be clear on the items above before opting and initiating the data migration.

Below are some of migration methods that can be considered:

1. Cutover Migration: - A cutover migration migrates all the existing mailboxes, contacts and distribution groups from an on-premises Exchange to Office 365.

The cutover migration is performed as a single batch move that includes all of the mailboxes, contacts, and distribution group objects. There is no option to selectively migrate objects. After the migration is complete, every user having an on-premises Exchange mailbox also will be a new user in Office 365.

When to choose cutover migration:

  • Current on-premises Exchange environment is Exchange 2003, 2007, 2010 or 2013.
  • Current on-premises has less than 2000 mailboxes.

[As per Microsoft : Even though cutover migration supports moving up to 2000 mailboxes, due to length of time it takes to create and migrate 2000 users, it is more reasonable to migrate 150 users or less.]

Impact:

The main logistical challenge with cutover migration is the need to reconfigure every users’ outlook profile to connect to Office 365.

  1. Staged Migration: - A staged migration migrates all the existing users and resource mailboxes from an on-premises Exchange 2003 and Exchange 2007 organizations to Exchange online.

Suitable for medium-sized organizations. This type of migration moves mailboxes to Office 365 over a period of time and all mailboxes will be hosted in Office 365 at the end.

When to choose staged migration:-

  • The source email system is Microsoft Exchange 2003 or 2007

[Organizations with Microsoft Exchange 2010 and 2013 staged migration is not available. Cutover or Hybrid migration can be used for these versions.]

  • The key requirement of Staged Migration is Directory Synchronization, you will have to replicate user accounts from on-premises Active Directory to Office 365 organization. 

In staged migration mailboxes are moved in batches over a period of time so there is a simple high level of coexistence during the migration. Users with mailboxes in Office 365 can send and receive emails from on-premises users and vice-versa, they can see each other in GAL but cannot share free busy information and cannot access delegates.

  1. Hybrid Migration:

With hybrid deployment we can integrate Office 365 with our on-premises Exchange servers and also with the existing directory services, facilitating synchronization and management of user accounts for both the environments.

Hybrid deployments provide rich features:

  • A Hybrid configuration wizard establishes federation and connectors between the On-Premises Exchange and Office 365 tenant.
  • With Hybrid deployments mailboxes can be natively moved (same as we move in On-Premises) In and Out of Exchange Online, it is possible to also keep some mailboxes on-premises and some on Office 365.
  • Password synchronization or single-sign-on (SSO) can be added so users can log on to both the environments with their on-premises credentials.

When to choose Hybrid Deployments:-

The source email system is Exchange 2010 or later.

Note: - If your on-premises Exchange organization is running Exchange 2007 or 2003, and if you want to connect your organization to Office 365, you must install at least one on-premises Exchange 2013 or Exchange 2010 Service Pack 3 (SP3) server. This server is used for hybrid deployment connectivity that seamlessly connects your on-premises Exchange and Exchange Online organizations.

To avoid the additional cost of an Exchange 2013 or Exchange 2010 SP3 server license, you may qualify for a free Hybrid Edition product key for Exchange 2013 or Exchange 2010 SP3.

  1. IMAP Migration:

Staged, cutover and Hybrid migration use outlook anywhere or Exchange Web Services (EWS) to connect to Office 365. Customers not using MS Exchange servers won’t be able to utilize Outlook anywhere or EWS. So, other migration methods like IMAP must be used in such cases.

It is possible to migrate the contents of user mailboxes from source email system to Office 365 using IMAP migration type. IMAP extract information from source mailboxes and then push to the Office 365.

The only limitation of IMAP migration is the process migrates mail items and it doesn’t migrate calendar, contacts, notes or other item types. There is also a limit of 5000,000 items and 50,000 total mailboxes.

Understanding Office 365 identity models:

There are three main identity models in Office 365 when we set up and manage user accounts. 

Cloud Identity: - Manages user accounts in Office 365 only. No on-premises servers are required to manage users, it's all done in the cloud. The cutover migration process provisions the user objects as a cloud identities automatically, though organization can use directory synchronization after completion of migration, if they want.

Synchronized Identity: - Synchronize on-premises directory objects with Office 365 and manages users on premise. You can also synchronize passwords so that the users have the same password on-premises and in the cloud, however they will have to sign in again to use Office 365.

Microsoft_v1.0.png

Img Source: https://support.office.com/en-us/article/Office-365-integration-with-on-premises-environments-263faf8d-aa21-428b-aed3-2021837a4b65?ui=en-US&rs=en-US&ad=US

Federated identity: - Synchronize on-premises directory objects with Office 365 and manage users on premise. The users have the same password on-premises and in the cloud, and they do not have to sign in again to use Office 365. This is often referred to as single sign-on.

Microsoft_v2.0.png

Img Source: https://support.office.com/en-us/article/Office-365-integration-with-on-premises-environments-263faf8d-aa21-428b-aed3-2021837a4b65?ui=en-US&rs=en-US&ad=US

Conclusion:

Cutover migration is like a single batch move and suitable for small organizations, staged migration moves mailboxes in batches and is suitable for the medium size organizations, Hybrid migration is a feature rich migration and gives us ability to natively move mailboxes.

Each migration method has its own pros and cons, however the impact can always be minimized with a pre-assessment of the source email environment and a proper migration strategy. For any questions click below:
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