Case study

EDF migrates from IBM Mainframe to Oracle RAC on Azure powered by FlashGrid Cluster


In a strategic move coincident with the shift to remote working and smaller offices absent of data centers, EDF are enacting a broad modernization initiative. This encompasses the upgrade of mission-critical application Asset Suite and refactoring integrations with key business systems. EDF found the ideal partnership with FlashGrid and Azure, unlocking new possibilities aligned with their evolving requirements.

Critical requirements

  • A performant and highly available (HA) Oracle database.
  • Scalability for a growing database, currently 4TB in size.
  • Compliance with ONR (Office for Nuclear Regulation) licence conditions for uninterrupted operation of EDF’s nuclear power stations in the UK, constituting 15% of the country’s energy production.


To meet the upgrade’s requirements, EDF had to depart from the familiar IBM zSeries mainframe Parallel Sysplex with DB2 data sharing database configuration and consider options compatible with Oracle Database.

After a thorough investigation, EDF chose FlashGrid Cluster for Oracle RAC on Azure. To further enhance the database’s resilience, they deployed Active-Active nodes spanning two Availability Zones with a Quorum in a third in Azure’s UK regions. This configuration protects against data centre failures and extreme disasters and ensures compliance with national regulations.

Navigating challenges with FlashGrid Support

FlashGrid’s early support played a pivotal role. The team’s concerns about matching the on-prem performance of a mainframe in the cloud were effectively addressed during a POC (Proof of Concept), empowering EDF to complete most of the work internally with minimal external assistance. While challenges emerged due to evolving requirements, requests for enhanced functionality, and rigorous testing, their database infrastructure was unaffected.

“Our internal team of DBAs, engineers, and lead solution architect spearheaded the transition to cloud computing. From the beginning, we could demonstrate it was feasible and that we could rely on a highly available Oracle database on Azure thanks to FlashGrid’s technology and guidance.”

Adam Ashby – Technical Project Manager at EDF

Easy adoption and ongoing success

EDF’s team underwent one-to-one training with FlashGrid, facilitating the adoption of database infrastructure on Azure cloud and leaving behind 20+ years of experience with their finely tuned (yet outdated) mainframe environment. FlashGrid Cluster’s intuitive interface and comprehensive documentation simplified the learning process. The recent flawless upgrade to the latest FlashGrid software version garnered satisfaction from the lead DBA.

EDF awarded top marks to FlashGrid’s technical support and could not suggest any improvements—a testament to the unwavering dedication of the support team.

Looking ahead, EDF plans to modernise other mission-critical applications and expand their cloud-based database infrastructure using FlashGrid Cluster for Oracle RAC on Azure. The partnership continues, unlocking even more possibilities.


With 67.33 million people consuming an average of 4,813 kilowatt-hours per year, the UK is among the largest consumers of electricity in the world. EDF is the UK’s biggest supplier of zero-carbon electricity and has over 60 years of experience running nuclear power stations. Their quiet and reliable service is underpinned by complex and robust technology systems that must function continuously every day of the year.

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