Disaster recovery (DR) is exercised on a planned (frequent monthly/quarterly service updates) and unplanned (unforeseen outage) basis. Planned DR exercise results are not shared with the public, but submitted to an auditor for compliance. DR is transparent to endusers and solutions implemented using managed .NET code. For unmanaged code, a small routine is required to ensure that the solution falls back to the correct DR URL as described in the following article:

https://msdn.microsoft.com/en-us/library/hh771583.aspx

The Dynamics 365/CRM Online service continuity program ensures that the platform is up and running, and that outages are kept to a minimum. For further details about service continuity, read the following TechNet article:

 https://technet.microsoft.com/pt-pt/library/jj134081(v=crm.7).aspx#BKMK_CRM_Online_Svc_Continuity.