Disaster recovery protection for cloned and restored RBD volumes

The CephCSI driver does necessary operations on the cloned or restored RADOS Block Device (RBD) volumes to prepare them for disaster recovery protection when you enable the disaster recovery support for restored and cloned PersistentVolumeClaims.

Cloned and restored RBD volumes are copy-on-write clones of the corresponding data sources. Such RBD volumes are still linked to the parent volume to optimize space consumption and Ceph cluster performance. To mirror RBD images that have such volumes, the cloned and restored RBD volumes need to be separated from the parent RBD image.

Selecting the Enable disaster recovery support for restored and cloned PersistentVolumeClaims (For Data Foundation only) checkbox while Creating Disaster Recovery Policy on Hub cluster instructs CephCSI driver to do necessary operations on the cloned or restored RBD volumes to prepare them for disaster recovery protection. The necessary operation has the following consequences:

Space consumption may increase up to the total capacity of all cloned and restored RBD volumes that are protected. Make sure that enough space available in the cluster so that the cluster does not full.
Resource usage of the Ceph cluster increases.
The time taken for the operation to complete depends on the number of the RBD volumes, size of each volume, Ceph cluster resource availability, and client IO going on the RBD volume. Therefore, the amount of time that is required for completion of the operation cannot be determined.