Taken from the dbench README file:
Netbench is a terrible benchmark, but it's an "industry
standard" and it's what is used in the press to rate windows
fileservers like Samba and WindowsNT.
In order for the development methodologies of the open source
community to work we need to be able to run this benchmark in
an environment that a bunch of us have access to. We need the
source to the benchmark so we can see what it does. We need
to be able to split it into pieces to look for individual
bottlenecks. In short, we need to open up netbench to the
masses.
To do this I have written three tools, dbench, tbench and
smbtorture. All three read a load description file called
client.txt that was derived from a network sniffer dump of a
real netbench run. client.txt is about 4MB and describes the
90 thousand operations that a netbench client does in a
typical netbench run. They parse client.txt and use it to
produce the same load without having to buy a huge lab. They
can simulate any number of simultaneous clients.