Typically, the source host would not be connected to the  failback volume (i.e., the site went down, host crashed, lost power,etc.) For testing you would first need to gracefully disconnect the host iSCSI connections to the failback volume in order to test you process. -joe
     On the DR vCenter, selecting Replicate to Primary Site, fails with the error below because the primary site still has connections to the LUN open. The work around is to set the LUN offline at the primary site but ESXi gets up set over this. Is this the correct method? Seems a little clunky to me. [IMAGE] 
ASM/VE - testing failback