Perhaps the greatest fear any IT manager has is downtime of the entire IT environment. When an enterprise IT environment fails—due to, for example, an on-premises datacenter outage—the results
can be catastrophic for a business. Moreover, when the outage is remediated, systems often must be brought back online in a particular order to smoothly restore operations.
The cloud presents a number of new opportunities for enabling business continuity and disaster recovery. (Data backup and recovery was discussed in the previous section.) Azure Site Recovery makes it possible for workloads to be quickly replicated to Azure, and to be restored in an orderly
fashion using Orchestrated Disaster Recovery as a Service (DRaaS). Enterprise IT professionals can
create recovery plans, dictating specifics such as which workloads must be run first, or only running a
workload upon the successful completion of an integrity check.
Using Microsoft System Center Virtual Machine Manager, you can replicate virtual machines (VMs) as well as physical servers to the Azure cloud under the control of site-defined policies. You can also
“burst” workloads to Azure when surges occur. Microsoft System Center Operations Manager will also monitor the operation of the on-premises systems from Azure, ensuring that failures are detected and managed as quickly as possible.
When planning a Site Recovery deployment, consider the following:
What are your Recovery Time Objective (RTO) and Recovery Point Objective (RPO)? RTO is the
time desired to bring an application or ecosystem back online; RPO describes the state of the
data after the system is recovered.
Which systems must you bring back up first, and which systems depend on others before you
can restart them? For example, it might be necessary for the database server to be online
prior to starting a web server or SharePoint system. Knowing this sort of information will aid
in building a recovery plan.
Source of Information : Microsoft Enterprise Cloud Strategy