From On-Prem to On-Call:
Executive Summary
A leading pediatric and women's health system partnered with Mission to migrate its Tier 3 workloads from an aging on-premise VMware environment into AWS. Facing a pressing licensing renewal deadline, the health system needed a proven partner to move hundreds of virtual machines quickly and cleanly. Mission delivered a structured, wave-based migration that hit every milestone on time, moving Tier 3 workloads into AWS without disruption.
About the Customer
The customer is a nationally recognized healthcare organization dedicated to exceptional care for children and women. It serves patients from across the country and beyond, and operates a research program committed to accelerating the path from diagnosis to treatment.
Scale faster without breaking your cloud
Background
The health system had existing workloads running within AWS but relied heavily on an on-premise VMware environment for its Tier 3 applications. A forthcoming licensing renewal created the urgency needed to accelerate its cloud journey. The organization engaged Mission through its relationship with CDW to execute the migration.
Challenge
The pressure was twofold. On-premise compute licensing costs were rising substantially ahead of a contract renewal cycle, and to accurately assess renewal costs, the incumbent hypervisor required a core-counting tool to run for six to eight weeks prior to the January deadline. That meant the health system had to reduce its on-premise core footprint before November, leaving a narrow window to move a significant volume of workloads.
Beyond licensing, the organization recognized that an on-premise model demanded large capital expenditures upfront, regardless of actual utilization. Test environments, ambulatory systems used only during weekday hours, and other intermittent workloads were costing money around the clock. The team needed a platform that matched cost to consumption. At the same time, internal staff capacity to manage an expanding infrastructure was finite, and the organization saw cloud migration as an opportunity to modernize how its team operated.
Why Mission
When the health system began evaluating partners for the migration, it sought organizations with proven depth, not just familiarity with the process. Its AWS representative pointed directly to Mission as a capable and trusted partner. What stood out was Mission's willingness to work hand-in-hand with the internal team, treating the engagement as a shared effort rather than a handoff. The knowledge transfer component mattered: the organization wanted to build internal competency so its staff could carry the work forward independently.
The timeline was aggressive, and the need for a partner that could meet a hard cutover date without disruption was non-negotiable. Mission fit that profile.
Why AWS
The health system chose AWS for its depth of native tooling built with healthcare and life sciences organizations in mind. The platform offered capabilities for artificial intelligence, big data, and advanced analytics without requiring external investments in third-party tools layered on top. The organization also had existing workloads already running in AWS, giving its team a familiar foundation. The availability of AWS-native monitoring, infrastructure management, and modernization services made it a logical platform for its longer-term technology strategy.
Solution
Mission began the engagement with its MAP Assess Factory, conducting a thorough discovery of the customer's existing environment using Cloudamize. The team catalogued the full application stack, reviewed networking architecture including DirectConnect configurations and Palo Alto firewall rules, and developed a detailed migration wave plan that separated development and production workloads.
Mission led the evaluation of 600 virtual machines in the initial assessment. Mission and the customer worked collaboratively to gauge each application for cloud readiness, removing workloads with local hardware dependencies, licensing constraints, or latency sensitivities from scope. This careful triage protected the project from avoidable complications downstream.
The migration itself ran on AWS Application Migration Service. Mission built baseline security groups, configured IAM permissions for AWS Systems Manager agent communication, and carefully vetted launch templates to confirm instance sizing, subnet placement, and resource adequacy for each wave. One noteworthy configuration requirement was a client preference to avoid AMD-based instance types, which required Mission to audit and recalibrate affected instances across the environment.
Each migration wave followed a consistent cadence: test instances were launched first, smoke tested by the Mission team, then decommissioned before production cutover instances went live. Application owners then conducted their own validation before systems were declared complete. A handful of machines required remediation for Windows boot mapping issues, which Mission resolved as part of the standard cutover process.
The project met the customer's tight deadline, closing with approximately 90% of Tier 3 workloads successfully running in AWS. The remaining ~10% represent a small number of applications which were returned to on-premise after surfacing undocumented local dependencies, a reflection of Mission's disciplined, collaborative approach.
Results
The health system hit its critical deadline, reducing its on-premise VMware core count before the incumbent hypervisor's inventory tool began its pre-renewal audit. That outcome was the primary commercial driver of the project, and Mission delivered it on schedule with no significant disruptions to hospital operations.
The new environment gives the organization a fundamentally different operational posture. Where it previously needed to provision, deploy, and absorb the full cost of physical hardware regardless of utilization, it can now scale capacity up or down based on actual need. Test environments and ambulatory systems used only during business hours can be paused over weekends, trimming costs without any clinical impact. Spinning up additional instances to support growth in a clinical specialty, a process that formerly required hardware procurement cycles, can now happen in minutes.
Disaster recovery improved considerably. Tier 3 workloads that previously replicated between two physical data centers now spread across multiple AWS availability zones, effectively placing systems across what equates to nine data centers in the region. Backup and recovery operations are cleaner and faster as a result.
The migration also created the conditions for longer-term modernization. The health system can pursue infrastructure-as-code (IaC) practices, integrate AWS-native monitoring through tools like Amazon CloudWatch and AWS Systems Manager, and eventually connect cloud operations to a more mature CI/CD pipeline. Right-sizing and cost optimization efforts are already scoped as the next phase of work.
Mission and the customer are currently working toward that next chapter, with internal staff now carrying firsthand AWS migration experience alongside Mission's continued guidance.
AWS Services
- Amazon EC2
- Amazon VPC
- AWS Application Migration Service (MGN)
- AWS Systems Manager (SSM)
- Amazon S3
- Cloudamize (discovery and assessment)