A program similar to iperf that uses “uncompressable” blocks of data to properly test the connection with compression

Question

Can anyone point to a program similar to iperf, which avoids biasing of the connection bandwidth measurement due to connection compression enabled?

It seems that iperf measures the connection spedd by sending some zero data across the connection. When measuring the connection with enabled compression (like openvp tunnel) such data that is sent is compressed effectively, and data transfer measurement is not accurate.

Please advise the program (or way to use iperf) so that the compression is negligible (like in case of sending the /dev/urandom or /dev/random prepared chunks).

Answer 1

Looks like I've found the solution: iperf itself has an option to use prepared data for transfer. The option is -F. In case we want to pipe the data from another application to iperf, one may use -I option (read data from stdin).

The test routine I used is as follows (using 1GB file):

dd if=/dev/urandom of=/tmp/urandom.dat bs=1M count=1000
iperf -c iperf-server -F /tmp/urandom.dat