Loadgen is an file traffic generator that can change its offerred load (quickly) in response to numeric input (how many threads) on stdin, and that reports actual achieved throughput regularly on stdout.
It is actually designed to be driven (as a horde of zombies) by a master program that manages load and collects and displays throughput data. Thus it may be desirable to turn lots of client machines into loadzombies that can be called into service when we need their help.
To turn an ordinary system into a loadzombie:
(1) install the appropriate (32/64) loadgen in /usr/bin.
(2) make sure that xinetd is installed
make sure that xinetd is running
# service --status-all
It may not yet be installed.
CentOS:
# yum install xinetd
# chkconfig --level 345 xinetd on
Ubuntu:
# apt-get install xinetd
(3) configure the loadzombie network service:
edit "loadzombie" configuration file to choose a port.
copy "loadzombie" configuration file to /etc/xinetd.d
# cp loadzombie /etc/xinetd.d
tell xinetd to rescan
# service xinetd restart
(4) test the loadzombie service:
% telnet <node> <port>
for <node> on which the service is configured (local = 127.0.0.1)
<port> on which the service is configured (default = 8081)
It should greet you with a loadzombie prompt.
If you enter 'x' followed by a newline, it
will shut down and close the port.
To use the zombiemaster console
(1) decide how many zombie servers you need, and do the above loadzombie server configuration on each.
The typical reason to use a large number of loadzombie servers is that
one client/initiator cannot generate enough traffic to seriously load
a storage (e.g. NAS or iSCSI) server.
(2) figure out what parameters you want to use for the load generation.
You can read the loadgen manual section and try tests with different
combinations of parameters until you get the test you want.
A few of these (e.g. bsize, length, rate, update) can be specified
as horde parameters. Others (e.g. target) must be specified per
zombie.
(3) figure out how you want to display this information on the console.
choose a title for the console window ("title" parameter)
choose a per-zombie throughput scale ("wire" parameter)
choose a whole horde throuhput scale ("scale" parameter)
(4) create a horde configuration file
start with the sample file in java_src
set the horde parameters with PARM lines
crate a ZOMBIE line for each zombie, specifying
tag= the unique identifier for this zombie
zombie= the host name or IP address
port= the port on which loadzombie is listening
all per zombie configuration parameters
(5) start up the zombie master
java -jar ZombieMaster.jar xxx name-of-horde-configuration-file
you might want to specify --DEBUG and capture stdout in a file
(6) set any other parameters on the console
e.g. operation, size
(7) click the start button to start all of the zombies
(8) click the whole-horde or per-zombie +/- buttons to change the number of active threads.
(9) click the stop button to stop all of the zombies
(10) click the exit button on the ZombieMaster window to shut it down