I just cleared A2 Inferno with my barb. The difficulty increase from A1 Inferno to A2 is huge! In A1 I can lure 3 elite groups to the warden and kill them all at the same time and solo down the butcher standing in the fire, but in A2 there are elites with certain affixes that are deadly that I have to skip, and the normal mobs hit so much harder.
Here's my stats which I believe is the minimum needed by a barb to clear A2 Inferno:
50k hp,
900 resist all
10k armor,
10k dps