Secure Migration of 100 TB+ Office 365 Data Between Tenants

Moving 100 TB+ of Office 365 data between tenants is easy and secure with CloudFuze Migrate.

At the enterprise level, it is important to coordinate Exchange Online, SharePoint Online, OneDrive, and Microsoft Teams while keeping permissions, metadata, version history, sharing links, and user access intact. It gets even more complicated during M&A, tenant consolidation, divestitures, and business restructuring when many users have to migrate to a different Microsoft 365 environment.

With CloudFuze, enterprises can perform large-scale migrations involving over 100 TB or even 10 PB of Microsoft 365 data using our enterprise migration platform with a managed service approach for planning, executing, monitoring, and validating high-volume and multi-tenant Microsoft 365 tenant migrations.

Why 100 TB+ Office 365 Tenant Migration Is Different

A 100 TB+ Microsoft 365 migration introduces challenges that are less significant in smaller tenant moves.

The data is distributed across multiple Microsoft 365 workloads, users, sites, Teams, permissions, and identity relationships. A tenant migration strategy therefore needs to address more than raw storage capacity.

For 100 TB+ Office 365 tenants to tenant migration, Exchange Online, SharePoint, and OneDrive, MS Teams are considered as the major tenant-to-tenant workloads and emphasize identity mapping and target-tenant preparation.

What Does a 100 TB+ Office 365 Migration Between Tenants Include?

A large Microsoft 365 tenant migration can involve several workloads.

1. Exchange Online/Outlook

Mailbox migration from Office 365 tenant to another can include:

• Email messages
• Mail folders
• Calendar data
• Contacts
• Attachments
• Email metadata
• Shared mailboxes
• Historical mailbox content

For Outlook/Exchange-specific migrations, see our guide to Outlook to Outlook migration for enterprises.

2. OneDrive for Business

OneDrive migrations can involve:

• Personal files and folders
• Folder structures
• Permissions
• Sharing links
• File versions
• Metadata
• User ownership relationships

For permission and external-sharing requirements, see our guide to OneDrive to OneDrive migration with external shares.

3. SharePoint Online

Enterprise SharePoint migrations can include:

• Sites
• Document libraries
• Files and folders
• Site permissions
• User permissions
• Group permissions
• Sharing links
• Version history
• Metadata

4. Microsoft Teams

MS Teams to Teams migration can require coordination between:

• Teams
• Channels
• Conversations
• Files
• Membership
• Associated SharePoint content

For bulk migrations, Microsoft advises using a Microsoft solutions provider such as CloudFuze Migrate if an organization has 500-10K+ users or massive amounts of SharePoint data. We offer migration of Microsoft Teams, Exchange Online/Outlook, SharePoint Online, and OneDrive for Business.

Are you looking to migrate 100 TB+ Office 365 Tenant data during M&A? Talk to our expert to help you plan your migration in the best way possible.

The Security Concerns of 100 TB+ Migration Between Microsoft Tenants

In cases where large volumes of corporate data get migrated from one Microsoft 365 environment to another, the IT team should be in control of who has access to the migration environment, how the connection between source and destination tenants takes place, what identity mapping should be done, and how to monitor the migration process.

1. Source and Destination Environment Connection Security

CloudFuze uses API and OAuth for connection and authentication in order to connect cloud environments, as opposed to using the Microsoft 365 credentials to authenticate the migration environment.

2. Identity Mapping

A source tenant and target tenant may use different:

• Domains
• UPNs
• Usernames
• Microsoft Entra ID identities
• Groups

For example:

CloudFuze can use CSV-based user mapping to associate source identities with destination identities before migration. This mapping becomes particularly important when preserving permissions across SharePoint and OneDrive.

3. Maintain Permission and Access Control

A file moved without its permission will pose a security risk.

CloudFuze supports migration of Microsoft 365 content and maintains permissions, share links, timestamps, versioning and other content relationships according to the workload and target configuration.

4. Maintain Metadata and Version History

Business data contains information other than the file itself. CloudFuze has the capability to migrate the Microsoft 365 data which will include historical metadata, timestamp, authorship, and versioning according to the supported workloads.

This will help businesses to maintain consistency when they are accessing historical business documents post tenant migration.

5. Delta Migration

A 100 TB plus migration can never be done in one migration window. Users keep working throughout the migration process. It means that new emails will keep coming in, documents will be changed, Teams’ conversation will happen, and files will keep getting edited.

The practical enterprise strategy would thus involve the following:

Pre-scan → Pilot → Initial migration → Delta synchronization → Cutover → Validation

CloudFuze offers delta migration support to ensure any new/updated data since the initial migration is synchronized before the cutover. We executed enterprise tenant consolidation projects using multiple incremental synchronization passes.

Concerned about security during a 100 TB+ tenant migration? Protect data, permissions, and access with CloudFuze’s secure migration capabilities. Request a free migration assessment today.

How to Migrate 100 TB+ Office 365 Data with CloudFuze Securely

100 TB+ migration within Microsoft 365 (OneDrive, SharePoint Online, Exchange Mailboxes, and Microsoft Teams) would need enterprise-level infrastructure architecture capable of handling Microsoft Graph API throttling, ensuring complex data fidelity, and securing zero-trust compliance.

CloudFuze handles petabyte-level migrations via dedicated cloud compute instances, multi-node parallelism, and dynamic App-Pool configuration.

Phase 1: Pre-Migration Architecture Planning

To perform migration of 100 TB+ data, it is necessary to first plan for the architecture and recognize possible risk areas within the source/target tenants.

1. Deploying Migration Infrastructure Dedicatedly

Dedicate cloud computing instances to the migration workload to ensure performance predictability while processing thousands of user accounts, sites, mailboxes, and files concurrently.

2. Configure Application Pooling

Set up multiple custom Microsoft Entra ID applications as necessary for your migration architecture. CloudFuze can load balance migration tasks using the configured application connections and manage concurrency to help mitigate the effect of Microsoft 365 API throttling.

3. Run Automated Discovery and Assessment

Run pre-migration assessment on the 100TB+ environment to identify:

• Large files and large volume repositories
• Complex folder hierarchies and long paths
• Inactive / orphaned accounts
• User mappings from source to destination
• SharePoint Sites & Document Libraries
• OneDrive Accounts
• Internal and external sharing settings
• Potential un-mapped users or groups
• Migration dependencies and exceptions based on specific migration workloads

The discovery and assessment help your IT teams prepare a migration inventory and decide the right migration waves.

Phase 2: Migration Execution Workflow

1. Set Up Secure Tenant Authorization

Connect your source and destination Microsoft 365 tenants via OAuth 2.0 and Microsoft Entra ID.

Enterprise application registration can be set up with permissions for the chosen workloads, as per the company’s security and least privilege policies. You do not need to give CloudFuze your user passwords.

2. Configure User and Permission Mapping

Map users, groups, mailboxes, OneDrive, SharePoint, and Teams from source to target.

CSV-based mapping is useful in cases where large migrations are needed where there is a change in domains, UPNs, organizational structure, or user identity in the migration process.

Example:

Source: user@companyA.com

Target: user@companyB.com

Migration mapping ensures that the migrated content and permissions map correctly to target identities.

3. Perform a Pilot Migration

Before performing the full 100 TB+ migration, perform a pilot migration involving representatives from various workloads and data types.

This could include:

• Exchange Online mailboxes
• OneDrive
• SharePoint sites & libraries
• Microsoft Teams
• File repositories with large and complex data structures

4. Perform the 100 TB+ Migration in Waves

After the validation of pilot migration, perform the production migration in waves.

CloudFuze supports simultaneous migrations of multiple workloads with workload specific migration control while processing multiple migrations at the same time. Migration team may perform the waves on:

• Department
• Business unit
• Geography
• Groups of users
• SharePoint sites
• Data volume
• Application dependencies

The process makes it possible for large volumes of data to migrate incrementally as opposed to migrating once at a high risk.

5. Perform Incremental Delta Synchronizations

During an ongoing migration process, users are continuously generating and updating content within the source tenant.

Delta Synchronization performs migration of changes after the first migration of newly created or changed supported content. Several passes of Delta Synchronization decrease the amount of data which will be required to migrate during the cut-over.

6. Finish Cut-over and Post-migration Validations

After the final Delta Synchronization process:

• Perform the necessary cut-over processes for tenants and identities.
• Validate the migrated users, sites, mailboxes, files, and permissions.
• Check the migration logs and reports.
• Identify and fix failed and unprocessed items.
• Verify target user access.
• Remove or revoke migration-related application access that is no longer required.
• Retain migration reports according to organizational audit requirements.

Watch This Step-by-Step SharePoint to SharePoint Online Migration Tutorial using CloudFuze Migrate

Optimization Techniques for Migrations Greater than 100 TB

• Workload Segregation: Isolate Exchange Online mailbox migrations from file migrations like OneDrive and SharePoint migrations. Perform each type of migration using specific threads to control API utilization and mitigate any issues related to throttling.
• Large File Segmentation: Leverage CloudFuze’s multipart streaming mechanism to break up large files into smaller chunks, making their transfer possible in a parallel manner. Network disruptions are less likely to cause failures because transfers will automatically resume.
• Migration of Microsoft Teams: Migrate Microsoft Teams’ channels, private chats, files, and tabs in well-organized stages. Doing so will allow for preservation of all the supported data in Microsoft Teams and validation of content before transitioning to the destination tenant.

Case Study: US IT Firm Migrates 120+ TB of Microsoft 365 Data Post-Acquisition

A US-based IT services company acquired a regional technology firm and needed to consolidate its Microsoft 365 environment into a single tenant. The acquired company had 120+ TB of data across OneDrive, SharePoint Online, Exchange Online, and Microsoft Teams, including 40 TB of OneDrive data, 55 TB of SharePoint data, 15 TB of Exchange Online mailbox data, and 10 TB of Teams-related data.

The IT team needed to complete the migration without disrupting employees’ day-to-day work and without losing existing permissions and data. CloudFuze helped the company assess the source environment, map users and permissions, and migrate the data in phased waves. Initial full migrations were followed by delta synchronization to capture changes made during the migration.

The migration enabled the company to consolidate the acquired organization’s Microsoft 365 environment while maintaining file structures, permissions, mailbox data, and supported Teams content, with zero disruption to users.

This approach gives the IT team a structured path from discovery to final tenant consolidation, rather than attempting to move 120+ TB in a single operation.

Why Enterprises Use CloudFuze for Large Office 365 Migrations: 100 TB+ to 10 PB+

At 100 TB+ to 10 PB+ scale, a successful migration requires more than high transfer speeds. Enterprise IT teams need an approach that addresses scale, security, identity mapping, permission preservation, incremental synchronization, monitoring, and validation.

CloudFuze offers a combination of its migration platform and managed migration services that facilitate complex Microsoft 365 tenant-to-tenant migrations. Our customers include a Fortune 500 IT service company that migrated two Microsoft 365 tenants that consisted of 6,850 mailboxes, 65 TB of OneDrive, 25 TB of SharePoint, and 420 Teams. This project was done through CSV-based user mapping and several delta synchronizations passes.

For organizations planning a 100 TB+ to 10 PB+ Office 365 tenant migration, this combination can help IT teams structure the project around controlled migration waves rather than a single high-risk cutover.

Migrate 100 TB+ of Microsoft 365 Tenant Data Securely with CloudFuze

CloudFuze offers an enterprise migration platform that enables secure transfer of Microsoft 365 data from one tenant to another tenant.

Planning a 100 TB+ Microsoft 365 tenant consolidation, acquisition migration, or divestiture? Request a migration assessment to evaluate your users, workloads, data volume, permissions, timeline, and migration strategy.

Frequently Asked Questions

1. How much time does a 100 TB+ Office 365 tenant migration take?

The duration will depend on a number of factors such as the number of users, workload, amount of data, API throttle, migration setting, and validation. It is possible that a large migration will take several months, especially migrating 100 TB+ of data across various Microsoft 365 workloads. CloudFuze offers fast and efficient migration abilities which enable enterprises to migrate large data in the set timelines.

2. Can CloudFuze perform migration of 100-200 TB+ of Microsoft 365 data between tenants?

Yes. CloudFuze migrates large data across Microsoft 365 tenant to tenant migrations for 100-200 TB+ data of OneDrive, SharePoint Online, Exchange Online, and Microsoft Teams. The migration plan may be divided into multiple phases depending upon users, workloads, departments, amount of data, or business units.

3. How does CloudFuze manage Microsoft Graph API throttling while performing a 100 TB+ migration?

In 100 TB+ migration, CloudFuze manages Microsoft 365 API throttle through application pooling, concurrency control and throttling management techniques. Migration workloads can be distributed across configured applications while adjusting the request rate in case of throttle.

4. Can CloudFuze ensure preservation of permissions in a tenant-to-tenant migration?

CloudFuze provides support for identity and permission mapping from source to target tenants. This enables the preservation of access relationships in the workloads supported by CloudFuze where the mapping of the identities between source and target is done properly.

5. Can users perform their tasks while the 100 TB+ migration takes place?

Yes. During a 100 TB+ or 10 PB+ migration with CloudFuze, the initial one-time migration can happen while the users keep working with the source tenant.

6. Does CloudFuze offer migration managed services for large Microsoft 365 migrations?

Yes, we do. Organizations can use CloudFuze migration platform in conjunction with migration experts that can help in discovery, planning, migration workload sequencing, monitoring, troubleshooting, and validation of migration. We make sure your migration is successful!