docs: add a document for DR overview

This document will aid as a landing page for
disaster recovery and will guide to the appropiate
documention that a user wants to go through
according to their need.
Further feature/documention enhancement regarding
rbd mirroring can have their linked docs listed
here for proper indexing.

Signed-off-by: Yug Gupta <yuggupta27@gmail.com>

Documentation/disaster-recovery-overview.md

@@ -0,0 +1,13 @@
+---
+title: Disaster Recovery Overview
+weight: 3240
+---
+
+# Planned Migration and Disaster Recovery with Rook
+
+Rook v1.6.0 comes with the new volume replication support and Ceph-CSI v3.3.0, which allows users to perform disaster recovery and planned migration of clusters.
+
+The following documents will help to configure the clusters, as well as track the procedure for failover and failback in case of a Disaster recovery or Planned migration use cases:
+
+* [Configuring clusters with DR](rbd-mirroring.md): Understanding RBD Mirroring and steps to set it up using rook.
+* [Async DR Failover and Failback Steps](async-disaster-recovery.md): Tracks steps for Failover and Failback in case of a Disaster or a Planned migration.