How we can find that particular Volumes is belongs to particular aggregate
Ok, dn't take this the wrong way, but you have been asking a lot of basic questions. You need to watch the WBT's or take basic training to get you up-to-speed on netapp.
Vol status will show you or aggr show_space -g
I Know the answer
aggr ststus aggrname
but question is how we can increase the raid group size .
Again that wasn't your question.. But anyways..
But, please attend some basic training. The community is very helpful but for basic questions, you should refer to the MAN pages
is quite convenient