How to do it...

1. How to properly failover after an orderly shutdown:
   • Stop all client's that are writing to the primary image
   • Demote the primary image located on the ceph cluster:

               # rbd mirror image demote data/image-1

1. • Promote the non-primary image located on the backup cluster:

                # rbd-mirror image promote data/image-1

1. • Validate image has become primary on the backup cluster:

                # rbd mirror image status data/image-1

1. • Resume client access to the image:

1. How to properly failover after a non-orderly shutdown:
   • Validate that the primary cluster is in a down state
   • Stop all client access to the ceph cluster that accesses the primary image
   • Promote the non-primary image using the FORCE option on the backup cluster, as the demotion cannot be propagated to the down ceph cluster:

                 # rbd-mirror image promote data/image-1

1. • Resume client access to the peer image
2. How to failback from a disaster:
   • If there was a non-orderly shutdown on the ceph cluster then demote the old primary image on the ceph cluster once it returns:

                 # rbd mirror image demote data/image-1

1. • Resynchronize the image only if there was a non-orderly shutdown:

                # rbd mirror image resync data/image-1

1. • Validate that the re-synchronization has completed and image is in up+replaying state:

                # rbd mirror image status data/image-1

1. • Demote the secondary image on the backup cluster:

                 # rbd mirror image demote data/image-1

1. • Promote the formerly primary image on ceph cluster:

                  # rbd mirror image promotion data/image-1