Hi Anand,
You can take consistency group snapshots with SC but the consistency groups are per controller, so you get one for each controller. It is a two phased process 1) cg start 2) cg commit.
SC uses following process assuming controller1:vol1,vol2 controller2:vol3,vol4
1) cg start controller1:vol1,vol2
2) cg start controller2: vol1, vol2
3) cg commit controller1:vol1,vol2
4) cg commit controller2:vol3,vol4
While all volumes are fenced via the cg start everything is consistent. However the commit where fencing is removed and snapshot taken is not guaranteed to happen at same time for both controllers and thus consistency cannot be guaranteed unless the application using the storage issues write dependent writes. Most if not all databases do this for example. This means if first write is not acked then another write wont be sent. If this is the case the combination of that plus the CG mechanisms ONTAP provides guarantees consistency. If this isnt the case you need to get application consistency.
Unfortunately I cant give you a yes or a no but hopefully this helps you drive toward a solution
Regards,
Keith