1. The way how to configure storage [1] is not correct, see the correct way here [2].
2. The example [3] does not mention controller.devfile.io/read-only` annotation and `pv_name` is not documented.

[1] https://access.redhat.com/documentation/en-us/red_hat_openshift_dev_spaces/3.6/html-single/administration_guide/index#configuring-storage
[2] https://access.redhat.com/documentation/en-us/red_hat_openshift_dev_spaces/3.6/html-single/administration_guide/index#checluster-custom-resource-fields-reference-checluster-custom-resource-devEnvironments-storage-settings
[3] https://access.redhat.com/documentation/en-us/red_hat_openshift_dev_spaces/3.6/html/user_guide/requesting-persistent-storage-for-workspaces#requesting-persistent-storage-for-workspaces-requesting-persistent-storage-in-a-pvc