Full Infrastructure Migration: From Aging On-Prem to Azure

The Problem

The organization’s core infrastructure, file shares, databases, and the legacy ERP platform handling day-to-day orders and operations, ran entirely on on-prem hardware that was approaching end of useful life. Every month it stayed in production meant rising maintenance and support costs, and a growing risk that an outright hardware failure could take down the ERP system the business depended on for order processing. Scaling with the business wasn’t an option either: the existing environment had no headroom to grow into, and no incremental fix, a hardware refresh, a patch here or there, would have addressed the underlying problem. The only real path to the flexibility and cost efficiency the organization needed was a full migration off on-prem infrastructure entirely.

The Approach

We led the migration of the organization’s core infrastructure, file shares, databases, and the legacy ERP platform, from on-prem servers into Azure. Given the criticality of the ERP system and databases to daily operations, the cutover was executed during a planned maintenance window, balancing a careful migration against a short, communicated downtime window rather than attempting a live cutover that risked data integrity issues.

The organization’s phone switch remained on-prem, kept outside the scope of the Azure migration by design. To maintain secure connectivity for remote employees accessing the newly migrated file shares, we implemented a Site-to-Site VPN connecting the on-prem Fortinet appliance to an Azure VPN Gateway, giving remote staff the same reliable access to shared drives they’d had on-prem. Remote employees’ phone access was handled separately through Cisco Jabber, keeping phone system continuity intact without routing voice traffic through the migration at all.

Technical Highlights

• Migration tooling: Azure Migrate handled discovery, assessment, and replication of on-prem servers into Azure, rather than a manual export/import approach.
• File shares: re-architected onto Azure Files (SMB) as a managed cloud file share, rather than simply lifting and shifting the existing file server as a VM.
• Database: migrated via native backup/restore into Azure SQL Managed Instance, moving off on-prem SQL Server onto a fully managed PaaS platform while preserving compatibility with the native restore process.
• Network architecture: the Azure VNet was segmented into function-based subnets, application, data, and management tiers, rather than a single flat network, aligning with standard tiered-security design.
• Connectivity: a Site-to-Site VPN between the on-prem Fortinet appliance and Azure VPN Gateway provided persistent, secure access to the migrated file shares for both office and remote staff.
• Scope discipline: the on-prem phone switch was deliberately excluded from the migration; remote employee phone access was handled independently through Cisco Jabber, isolating voice infrastructure from the cutover entirely.

The Outcome

The organization moved off aging, costly on-prem hardware onto Azure infrastructure built to scale with the business, addressing all three original drivers behind the project: hardware age, cost, and growth capacity. Remote employees retained secure, reliable access to file shares throughout the transition via the Fortinet VPN, and phone system continuity was preserved for remote staff through Jabber, with zero disruption to a system that was intentionally kept out of the migration’s scope. The planned maintenance window approach meant the organization experienced a contained, expected downtime period rather than the risk of an uncontrolled cutover to critical ERP and database systems.