A 344-instance healthcare estate migrated to AWS 66% below its lift-and-shift baseline
The challenge
Healthcare estates are Windows-dense, and this one was no exception. Under a standard shared-tenancy model, Windows Server licensing accounted for $330,427 of the annual bill, the largest single line after compute itself. SQL Server licensing added a further $165,564.
The provider's actual licence position told a different story. They held 930 cores of Windows Server Datacenter against a modelled requirement of 192. Roughly four fifths of the entitlement sat unused, while the default migration model proposed paying AWS to licence the same workloads a second time.
The SQL Server position was tighter but favourable: 8 cores of Enterprise with active Software Assurance against 12 required, and 120 cores of Standard against 120 required. Close enough that a rigid all-or-nothing BYOL decision would have forced an unnecessary procurement over a four-core shortfall.
The estate also carried 21 virtual desktops on legacy VDI infrastructure and a disaster recovery requirement across the full in-scope footprint, neither of which appeared in a compute-only cost model.
Our approach
We right-sized the estate against measured utilisation, then built a mixed-tenancy design rather than forcing a single tenancy model across everything:
- 162 instances packed onto four EC2 Dedicated Hosts under both Windows Server and SQL Server BYOL, drawing on the provider's pre-October-2019 Datacenter entitlement
- 182 instances on shared tenancy, where the workloads were better served by elasticity than by licence recovery
- Four uncovered SQL Server Enterprise cores modelled as licence included rather than triggering a procurement for a four-core gap
We priced two further workstreams alongside the core model so the provider could evaluate a complete operating position:
- Legacy VDI to Amazon WorkSpaces across the 21 desktops
- AWS Elastic Disaster Recovery across all 344 in-scope servers, giving continuous replication into a low-cost staging area without duplicate infrastructure or duplicate licensing
The results
Windows Server licensing fell from $330,427 to $175,691 a year, a saving of $154,736.
SQL Server licensing fell from $165,564 to $13,140 a year, a 92% reduction, with only four Enterprise cores remaining on licence included.
Together, the two BYOL decisions removed $307,160 a year of vendor licensing from the AWS bill.
The recommended position at $588,264 sits 66% below the on-demand lift-and-shift baseline and 35% below a like-for-like right-sized shared-tenancy model.
Right-sizing, CPU optimisation and SQL Server consolidation reduced the forward database requirement from 10 Enterprise cores to 4 and from 106 Standard cores to 80. Virtual desktop replacement priced at $16,207 a year across 21 users. Full-estate disaster recovery priced at $280,702 a year.
Why it matters
A licence-included migration is the fastest to model and the most expensive to run. Where a customer holds pre-October-2019 volume licences, a mixed-tenancy design almost always justifies the additional planning effort.
Here it removed $307,160 a year from the AWS bill while leaving 738 Windows Datacenter cores available for future growth, which the provider can now deploy against new workloads instead of buying capacity it already owns. Recognising that the entitlement existed was worth more than any single architectural decision in the engagement.
Collection for this engagement ran through AWS Migration Evaluator. What that tool can and cannot see: read the tool page →
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