When planning a BC / DR strategy it is important to understand:
- RPO (Recovery Point Objective) i.e. the maximum time in minutes for which data loss is acceptable when recovering from a disaster
- RTO (Recovery Time Objective) i.e. the maximum time in minutes it takes to recover service in the event of a disaster
- Synchronous vs. Asynchronous replication i.e. whether operations are carried out at the same time or queued
- SLA (Service Level Agreement) for the underlying services
When designing high availability into Azure services consider:
- Use of Availability Sets and load balancing for Virtual Machines
- SQL Server AlwaysOn (=> 3 node WSFC – Primary Replica, Secondary Replica, FSW)
- SQL Mirroring
Hyper-V Replica provides asynchronous replication of VMs without a shared storage requirement however shared storage can be leveraged with supported SANs for additional functionality. Azure Site Recovery also works wtih Hyper-V Replica.
System Center can provide orchestration for Site Recovery failovers.