Home > Storage > Data Storage Essentials > Storage Resource Manager (SRM) > Dell SRM: Disaster Recovery and Federated Architecture > Introduction
In this section, we focus on a case where the presentation and database layer components are replicated to a DR site.
The collection layer is distributed across remote sites that are not part of the DR replication mechanism.
If there is a PROD site failure, all the solution layers affected must continue providing service on another site. Service continuation is based on a predefined recovery time objective, which is the maximum time needed for restoring data access.