Amazon EBS io2 volumes now support shared storage fencing through NVMe reservations. For clustered applications that leverage EBS Multi-Attach capability of io2 volumes, NVMe reservations enables safe write access across the cluster nodes. Clustered applications are designed to increase application availability and scalability by using multiple compute nodes that coordinate access to shared storage. You can now use Multi-Attach on io2 volumes to deploy clustered Windows and Linux applications that require storage-layer fencing, such as SQL Server Failover Cluster Instances (FCI), within a single Availability Zone.
Source:: Amazon AWS