LDoms Manager (any version) cannot detect the same domain being 'bound' or 'started' to a different physical machine. The preferred way to do what you are attempting to accomplish is with LDOM migration (ldm migrate). To use LDOM migration the domain is created ONLY on host A. Both host A and host B must have the same vds servers, vdsdevs (for the LDOM), and the same virtual switches (going to the same networks) defined. Once the backend work is done and the LDOM is created, you can then "ldm migrate <LDOM> <Alternate Host>". This method will not have the same domain running on multiple hosts (A or B) at the same time because the LDOM is only defined on a single host.