[Hadoop-common-user] Wich is better Namenode and JobTracker run in different server or not?

It's unnecessary to run the NN and JT daemons on separate machines in small
clusters with more than three nodes. You'll only have performance benefits
by putting these daemons on separate machines if you have a large (100s of
nodes) cluster. It makes sense to separate the NN and JT daemons in a three
node cluster as well, assuming each node is a DataNode and TaskTracker as
well.

Hope this clears things up.

Alex