Hi Ricky, The input splits contain the locations of the blocks they cover. The AM gets the information from the input splits and submits requests for those location. Each container request spans all the replicas that the block is located on. Are you interested in something more specific?
-Sandy On Mon, Oct 28, 2013 at 7:09 PM, ricky lee <rickylee0...@gmail.com> wrote: > Well, I thought an application master can somewhat ask where the data > exist to a namenode.... isn't it true? If it does not know where the data > reside, does a MapReduce application master specify the resource name as > "*" which means data locality might not be preserved at all? thx, > > r >
