Software raid is not activated on multipath devices during boot

Issue

Software raid is not activated on mutlipath devices during boot. It must be activated manually with mdadm -As when the machine is rebooted,

[root@rehl6 ~]# cat /proc/mdstat 
Personalities : 
unused devices: <none>

mdadm -As must be used to get software raid active:

[root@rehl6 ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 dm-2[0] dm-1[1]
      10477440 blocks super 1.2 [2/2] [UU]