You can use the Object Storage Management application or API methods to mark a storage component as read-only.
Storage components are not automatically marked as read-only mode if they become completely full. You might mark a storage component as read-only if it is nearly full.
Once you mark a storage component as read-only, write requests are directed to different storage components.
You can only mark a storage component as read-only if it is marked read-write and in the state ACTIVE.