Inside a Fortune 500 Tenant Migration: What CloudFuze Did
Migration from one Microsoft 365 tenant to another becomes much more complicated when companies merge, acquire one another, or go through restructuring phases.
In this Microsoft 365 tenant migration case study, learn how CloudFuze helped a U.S.-based Fortune 500 IT services company carry out a large-scale migration from one Microsoft 365 tenant to another before the deadline with 100% data fidelity and uninterrupted operations.
Please note that the company name is withheld upon request for confidentiality purposes.
Key Takeaways:
Tenant Migration Case Study: How a Fortune 500 IT Services Company Consolidated Microsoft 365 After an Acquisition
Customer Overview & Migration Scope
After a recent acquisition, a U.S.-based Fortune 500 IT services company required migrating from two distinct Microsoft 365 tenants to a single target tenant. The scope of migration included:
- 6,850 Microsoft 365 user mailboxes
- 65 TB of OneDrive for Business
- 25 TB of SharePoint Online
- 420 Microsoft Teams
The Constraint: There was a strict deadline to complete the migration process before the end of the Microsoft 365 license for the acquired entity.
The Challenges: Difficult Workloads & Zero Downtime
There were some major friction points during the operations handled by the internal IT engineering team:
- Licensing Deadline: Performing a migration that involves multi-terabytes of data within a strict time window to avoid unnecessary licensing renewal costs.
- Permission/Hierarchy Protection: Migrating OneDrive/SharePoint content with full protection of intricate Access Control Lists (ACL), versioning history, and folder hierarchies.
- Email Integrity: Moving full metadata of the mailbox including email threading, calendar invites, contacts, shared mailboxes and read/unread state.
- Throttling Mitigation: Managing the strict throttling of the Microsoft Graph API and EWS across multiple data feeds.
- Business Continuity: Ensuring zero disruption for thousands of consultants using M365 to deliver clients’ work.
The Solution
The organization decided to use CloudFuze Migrate for an automated API-based cross-tenant migration process. The CloudFuze team implemented the following steps:
- Automated discovery of all users, shared mailboxes, SharePoint sites and permissions in both source and target Microsoft Entra ID tenants.
- Created and validated CSV-based mappings of User Principal Names (UPNs), primary SMTP addresses, and secondary aliases between the source and target tenants.
- Executed a pilot pass using 150 sample power users to validate the performance, permissions, and delta sync behavior of the migration.
- Grouped the remaining users by business unit and processed migration waves in parallel using CloudFuze’s dynamic API rate-limiting engine.
- Completed three delta sync passes before the cutover to move updated items without interfering with current users.
Results & Key Milestones
The project was completed ahead of schedule. This allows the IT team plenty of time to complete validation work prior to license expiration.
| Metric | Outcome |
|---|---|
| Migrated Mailboxes | 6,850 User Mailboxes |
| OneDrive Data Migrated | 65 TB |
| SharePoint Data Migrated | 25 TB |
| Microsoft Teams Workspaces | 420 Teams |
| Project Timeline | Completed well ahead of licensing deadline |
| Migration Success Rate | 100% |
| Delta Sync Cycles | 3 incremental synchronization passes |
| Critical Data Loss | 0 Items |
| Average Downtime | 0 reported downtime |
Business Impact
By unifying both the tenants of Microsoft 365 to a single environment, the organization simplified its administrative management process. It reduced any duplicative license expenses and created a common collaboration portal for the combined workforce.
Using the CloudFuze API-based migration platform along with CSV-based user mapping, and delta synchronization, the IT team managed to achieve a 100% success rate of data migration without any data loss.
Customer Testimonial
CloudFuze made a complex Microsoft 365 tenant migration surprisingly manageable. Their migration engineers worked closely with our IT team from planning through cutover, helping us migrate thousands of users with ZERO disruption. The platform preserved our mailbox metadata and OneDrive permissions exactly as expected. This helped our employees get back to work immediately after migration.
– Senior IT Infrastructure Manager, Fortune 500 IT Services Company
Ready to Replicate This Success?
See how CloudFuze can help you migrate Microsoft 365 tenants with minimal downtime, complete data integrity, and expert guidance. Schedule your free migration assessment today.
Frequently Asked Questions
1. How much time does it take to migrate Microsoft 365 tenants?
It depends on the number of users, data, and the type of workload that is going to be migrated. At CloudFuze, we have already helped many organizations migrate thousands of Microsoft 365 users in as little time as possible using migration waves, parallel processing, delta synchronization, and other techniques.
The migration specialists at CloudFuze work hand in hand with your IT department to create a migration strategy that will help to keep your project on track.
2. Is it possible to migrate OneDrive from one tenant to another while preserving permissions?
Yes, at CloudFuze we use our API-based migration tool to migrate OneDrive from one tenant to another while preserving folder structure, permissions, timestamps, version history and other necessary information about files. We even validate migrated permissions after cutover to make sure that users will have access to all the files.
3. What are the biggest risks in a Microsoft tenant migration?
The biggest risks include data loss, user mapping errors, permission issues, API throttling, and downtime. CloudFuze minimizes these challenges through pre-migration assessments, user mapping, intelligent throttling management, delta migrations, and detailed reporting, with expert engineers overseeing the entire process.
4. Can users continue working during a Microsoft 365 tenant migration?
Yes. CloudFuze performs migrations in the background, allowing users to continue working in Microsoft 365. We perform ZERO downtime migration every time.
5. How do you validate a Microsoft 365 tenant migration after cutover?
CloudFuze provides detailed migration reports to verify mailbox data, OneDrive and SharePoint content, permissions, and metadata. Our migration engineers also support post-migration validation to help ensure the new environment is fully ready for production use.
About the Author: Aayushi Raj
