Client Overview
The client operates as a collection of organisations covering estates, visitor attractions, hospitality, events, finance, HR and other group‑wide functions. Their environment includes around 1,300 employees, with approximately 600 already using Microsoft 365 services such as Exchange P1 email. Many departments worked from traditional on‑premises Active Directory environments and relied heavily on mapped file shares for day‑to‑day operations.
The Group sought to modernise its digital workplace by replacing fragmented on‑premises file systems with Microsoft Teams‑based collaboration across business units, improving access, security, governance, and mobility.
The Challenge
The group faced multiple issues originating from their legacy file‑share infrastructure:
- Distributed on‑premises departmental shares across multiple file servers, with inconsistent structures and permissions.
- Large data volumes, including home drives exceeding 10GB per user, with several users storing more than 70GB or even 103GB of files in their home directories. These volumes made migrations time‑sensitive and operationally difficult.
- Performance constraints from on‑prem servers, network throughput, and Microsoft 365 throttling, producing variable throughput of 0.5–1.6 files per second during migration tests.
- High user count of more than 536 home drives requiring careful planning around data volume limits and migration prioritisation.
- Existing architecture required a new Teams and site design, including governance, permissions, lifecycle management, cross‑organisational access, and naming conventions.
The organisation needed a structured, scalable approach that unified storage, simplified collaboration, eliminated duplication, and ensured that Teams governance standards were met from day one.
The Solution
Intelligent Decisioning designed and delivered a comprehensive Microsoft Teams & Microsoft 365 Modernisation Programme for the Group.
1. Information Architecture & Teams Design
ID produced a full Microsoft Teams Design for the Group, covering:
- Teams structure across organisations, departments and functions
- Entra ID group architecture and membership models
- File storage mapping from legacy shares into Teams, SharePoint and OneDrive
- Governance, compliance, permissions and sharing policies
- Lifecycle management and cross‑organisational collaboration controls
This design established how on‑premises organisational, departmental and functional file shares would be replaced with Teams‑based file repositories as part of Phase 1.
A detailed Teams/site catalogue for the Group was also compiled, covering business areas such as Estates, Group Marketing, CFO Office, People Team, HR, Payroll, IT and more, with corresponding private channels and access structures.
2. Migration Strategy & Planning
ID authored a dedicated On‑Prem to Microsoft Teams Migration Plan for the Group, including:
- Migration planning checklist
- Prerequisites and required permissions
- Mapping file structures to appropriate Teams
- Use of centrally managed migration agents
- Deployment of migration tooling within the Groups on‑prem infrastructure
- Handling file size limitations and agent distribution for performance scaling
The plan emphasised consolidating information into fewer, better‑structured Teams based on new agreed ways of working.
3. Migration Tooling & Automation
Multiple tools and automation approaches were incorporated:
- SharePoint Migration Tool (SPMT): primary tool for file‑share‑to‑Teams migrations, used across multiple servers to distribute load.
- Wayfarer migration tooling: for structured movement of file shares into Teams/SharePoint.
- PnP PowerShell / Microsoft Graph: for automated provisioning of Teams, channels, and configuration.
- ShareGate Migrate: for preserving ACLs, reviewing structures, and governing the environment post‑migration—used via a trial extended by ShareGate
- Power Automate: for workflow automation, approvals and lifecycle processes.
4. Performance Testing, Data Reduction & Risk Mitigation
ID conducted extensive performance tests against real user data volumes showing:
- Up to 22,825 files per migration batch
- Data sizes up to 103.92 GB for individual home drives
- Migration durations exceeding 30 hours for large volumes on existing infrastructure
Based on findings, ID recommended:
- Migrating the most recent 3 months’ data first
- Reducing bulk volumes for high‑usage users
- Staggering migration windows
- Implementing user guidance on H: drive size limits
- Using mapping files maintained by the Chatsworth project team for controlled batch execution
5. Stakeholder Engagement & Governance
The project included:
- Workshops with business units to define Teams structure, content ownership, and governance requirements.
- Engagement with stakeholders across the Group departments.
- Ongoing consultancy and alignment with finance, IT, HR, operations and marketing teams.
- Ensuring readiness for large‑scale M365 adoption across the estate.
The Results
The migration from traditional file shares to Microsoft Teams delivered major benefits:
Unified Cloud‑Based Collaboration
File access is now centralised within Microsoft Teams and SharePoint, providing:
- Reduced reliance on on‑premises servers
- Secure access from desktop and mobile
- Standardised storage locations across all companies in the Group
Improved Governance & Security
The governance model developed by Intelligent Decisioning ensures:
- Clear permission boundaries using Entra ID group structures
- Strong compliance, lifecycle and retention controls
- Reduction in shadow file storage and duplication
Operational Efficiency
- Consolidation of dozens of legacy file shares into structured Teams workspaces
- Automated provisioning accelerated rollout and minimised errors
- ShareGate and SPMT migration processes reduced manual overheads
Scalable Design for Future Growth
The new environment enables additional phases, including:
- Migration of image repositories into Organisational Asset Libraries
- Expansion of Teams usage across seasonal, operational and estate‑level departments
- Continued modernisation of business processes using the Microsoft 365 platform
Conclusion
Intelligent Decisioning delivered a structured, high‑quality migration for the Group, moving them from fragmented, difficult‑to‑manage file shares into a modern Microsoft Teams environment supported by strong governance and automation.
This transformation now provides:
- A modern, secure digital workplace
- Clear organisational structures aligned to operational needs
- Improved collaboration across multiple estates and business units
- A scalable foundation for future digital transformation across the Group
