I found I forgot to mention my hadoop version. I am using 0.19.1.
Thanks again, -seunghwa On Fri, 2009-07-17 at 18:57 -0400, Seunghwa Kang wrote: > Hello, > > I am running Hadoop on my 4 nodes system. > > Initially, I pick the replication factor of 2, and nearly 100% of map > tasks run in local up to 3 nodes, but the ratio drops to 80% if I use > all 4 nodes. > > As my nodes have quite high I/O bandwidth (24 disks per node), but > only > limited network bandwidth (1 GigE), this really hampers the > scalability. > > Just for test purpose, I increase the replication factor to 4, and > check > that input data actually has replication factor of 4 with 'hadoop fs > -stat %r%n' but find that the ratio is still around 80% for 4 nodes. >
