Merge pull request #1379 from openshift-cherrypick-robot/cherry-pick-1373-to-18.0-fr5

[18.0-fr5] updated backup command

Author: openshift-merge-bot[bot]

docs_user/modules/proc_adopting-the-block-storage-service.adoc

@@ -349,13 +349,18 @@ $ openstack volume backup list
 $ openstack volume create --image cirros --bootable --size 1 disk_new
 ----
 
-.. Back up the previous attached volume:
+.. If you deployed and adopted the `cinder-backup` service, back up the previously attached volume:
 +
 ----
-$ openstack --os-volume-api-version 3.47 volume create --backup <backup_name>
+$ openstack volume backup create <volume_name> --name <backup_name>
 ----
 +
-* Replace `<backup_name>` with the name of your new backup location.
+where:
+
+`<volume_name>`:: Specifies the volume that you want to back up.
+Replace `<volume_name>` with the volume you want to back up.
+`<backup_name>`:: Specifies the name of your new backup.
+Replace `<backup_name>` with the name of your new backup.
 +
 [NOTE]
 You do not boot a {compute_service_first_ref} instance by using the new `volume from` image or try to detach the previous volume because the {compute_service} and the {block_storage} are still not connected.