Microsoft has announced that Windows Server 2022 and Windows Server 2025 Failover Clusters now officially support running Storage Spaces Direct (S2D) CSVs (Cluster Shared Volumes) and traditional SAN (Fibre Channel/iSCSI) LUN CSVs within the same cluster. While today’s update allows them within the same clusters, they’ve been supported separately for a while. Failover Clustering has supported SAN since Windows NT 4.0 and S2D since Windows Server 2016.
The Redmond giant introduced this change in direct response to feedback from customers. It was a main request from customers who were looking to reuse existing SAN investments while migrating to or building out a new Hyper-V/S2D platform.
The key benefits of supporting SAN and S2D in the same cluster are flexible data migration and enhanced data strategy for customers. The move allows admins to use existing SAN as a source or destination for migrating data and VMs to and from S2D storage. Microsoft recommends the Hyper-V VM Storage Live Migration (“Move Virtual Machine Storage”) feature for moving VMs between S2D and SAN storage without VM disruption.
Customers can now also use high-capacity SANs for backup and restore operations, which gives organizations enhanced ransomware protection. You can also benefit from the strengths of S2D and SAN for storing and managing AI and ML workloads.
Admins should be aware of some important technical notes about the implementation. Microsoft highlights that SAN disks are excluded from the S2D storage pool, and S2D must only use Direct Attached Storage (DAS). It also mentioned that SAN volumes should be formatted as NTFS before adding them to CSVs, and S2D volumes should be formatted as ReFS.
With this update, Microsoft provides its enterprise customers with greater choice and flexibility in storage architecture, allowing them to combine the speed of S2D with their established SAN investments. Microsoft said that you can send your questions, comments, and feature requests about S2D and SAN Coexistence to: [email protected].