HP 3PAR Operating System Software - Manual (Page 258)

a group to be created, or a volume to be added to a group, only on one side of the pair if
the operation is interrupted by a network failure. In such cases it might be necessary to
temporarily change the policy to no_mirror_config in order to bring the configurations
into alignment. After being corrected the mirror_config policy should be immediately
restored. Such operations should generally only be undertaken on the advice of a HP
representative.
258 The Remote Copy Commands