In general, stretch clustering on Azure Stack HCI is an ideal DR solution for the following scenarios:
In an active/passive setup, business consumers actively connect to a preferred site for their application and workload resources. The infrastructure at the secondary site essentially remains idle until a failover occurs. When a failover occurs, active workloads are restarted at the secondary site, and business consumers connect to their applications running on that secondary site.
In an active/active setup, replication occurs bidirectionally from either site. Business consumers connect to active applications in both sites at any given time. This setup tends to be a more efficient use of an organization’s investment in infrastructure because resources in both sites are being used.
The Storage Replica service supports synchronous and asynchronous replication:
Mirrors data across low-latency networks with crash consistent volumes to help ensure that no data loss occurs at the file system level during a failover. This replication technique enables workloads to come back online automatically. With synchronous replication, data blocks are written to log files on both sites before being committed.
Mirrors data across greater distances over networks with higher latencies. This strategy does not guarantee that both sites have identical copies of the data at the time of failure. This replication technique does not enable workloads to be brought back online automatically after a failover. With asynchronous replication, the remote node accepts blocks of replicated data and lazily acknowledges back to the source copy.