ssh-vs-rsh benchmark result
I've tried running ssh and rsh on a local cluster, for your interest.
The experiment was ran on 60 nodes of a idle PC cluster,
each node is a dual-Pentium III 1GHz, memory 512MB,
interconnected with 100BASE-TX connection.
I have timed the following cases:
dsh -a w 3.748 -- running "rsh w" on all hosts sequentially
dsh -a -c w 1.170 -- running "rsh w" on all hosts parallelly
dsh -a -rssh w 23.051 -- running "ssh w" on all hosts sequentially
dsh -a -rssh -c w 4.306 -- running "ssh w" on all hosts parallelly
The time is in seconds.
I think it is rather significant.
Starting a job using rsh for 60 nodes takes only 4 seconds,
but running ssh for 60 nodes in sequence takes more than 20