High availability:
critical application components are load balanced across the two data centres in an active-active mode. This real-time mirroring across the data centres means that there is always a data centre live and available: if one should falter, access would default to the other.
Warm Data Recovery:
application components are replicated between the data centres and can be brought up manually in the case of a disaster being declared. Both centres replicate one another exactly and only one is live and active. Where one should falter, the other is automatically activated for access.