Basic limitations
Limitations
There are some basic limitations for distributed testing. Here's the list of the known items in no
specific order.
1. RMI cannot communicate across subnets without a proxy; therefore neither can jmeter without a
proxy.
2. Since JMeter sends all the test results to the controlling console, it is easy to saturate the
network IO. It is a good idea to use the simple data writer to save the results and view the file
later with one of the graph listeners.
3. Unless the server is a large multi processor system, in most cases 1-2 clients is sufficient to
overwhelm the server.
4. A single JMeter client running on a 2-3Ghz CPU (recent cpu) can handle 300-600 threads
depending on the type of test. (The exception is the webservices). XML processing is CPU
intensive and will rapidly consume all the CPU cycles. As a general rule, the performance of XML
centric applications will perform 4-10 slower than applications using binary protocols.
Additional resources
Tips
In some cases, the firewall may still be blocking RMI traffic.
Symantec Anti Virus and Firewall
In some cases, Symantec firewall needs to be stopped from windows services.
1. open control panel
2. open administrative tools
3. double click services
4. Go to down to symantec anti virus, right click and select stop
Windows firewall
1. open network connections
2. select the network connection
3. right click and select properties
4. select advanced tab
5. uncheck internet connection firewall
Linux
On Suse linux, ipchains is turned on by default. For instructions, please refer to the "remote testing"
in the user manual.
On RedHat (or derivatives), iptables (netfilter) is turned on by default. Execute "service iptables
stop" to stop the Linux netfilter firewall.
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