Testing network bandwidth using the NET IPERF command

Published 16 Feb 2014 Read time 3 min(s) 52 sec(s) (3884 views). Storage

This article describes how to collect and use network throughput measurements which are used for evaluating the performance of specific services that run on the data domain system.

Network throughput is measured between two systems. One system is the data domain system, whilst the other system can be any of the following:

A replication partner data domain system
Another computer system configured as a media server
Another computer system configured as a client

To measure the network throughput, use iperf. This tool is a commonly used freeware network testing tool that creates TCP and UDP data streams and measures the throughput.

iperf has two modes server and client.

Server mode is used on the source system and measures performance from the source (server) system to the destination (client) system.
Client mode is used on the destination system and measures performance from the destination (client) system to the source (server) system.

The data domain system being evaluated is tested as both the source and the destination system. This measures throughput in four directions:

Data Domain system as source system

iperf in server mode on data domain system as source
iperf in client mode on other system as client

Data Domain system as destination system

iperf in server mode on other system as source
iperf in client mode on data domain system as client

Determine OS version and download iperf

Verify that the data domain OS is version 4.7 or greater:
```
# uname
Data Domain OS 4.7.3.0-140348
```
NOTE: If the other system connected to the Data Domain system is another Data Domain system, verify its Data Domain OS version is 4.7 or above using the same command from its command line.
Download and install iperf if it is not already installed. You can download iperf from http://sourceforge.net/projects/iperf Use the installation instructions provided on the download web site.

Measure throughput with the data domain as the server

Obtain the IP address of the data domain system. Type the net show settings command at the data domain system command prompt, For example:

# net show settings
port    enabled   DHCP   IP address         netmask            additional setting   
-----   -------   ----   ----------------   ----------------   ------------------   
eth0    yes       no     192.168.4.118      255.255.252.0   
eth1    yes       yes    (not specified)*   (not specified)*   
veth0   no        n/a    n/a                n/a   
veth1   no        n/a    n/a                n/a   
veth2   no        n/a    n/a                n/a   
veth2   no        n/a    n/a                n/a   
-----   -------   ----   ----------------   ----------------   ------------------   
* Value from DHCP

Make a note of the IP address of the data domain system.

Run iperf in server mode from the data domain system. From the data domain system command line, type:

# net iperf server
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size:   256 KByte (default)
------------------------------------------------------------

Run iperf in client mode from the other system networked to the data domain system.

If the other system is a data domain system, at the other system command prompt, type:
```
# net iperf client <ip address> duration 60 interval 10
```
If the other system is a client computer system, at the computer system command line, type:
```
# iperf -c <ip address> -t 60 —i 10
```

The test will complete in 60 seconds. Review the output to determine the available bandwidth. Sample client output:

o    ------------------------------------------------------------
o    Client connecting to 192.168.4.52, TCP port 5001
o    TCP window size:   256 KByte (default)
o    ------------------------------------------------------------
o    [  3] local 192.168.4.118 port 36588 connected with 192.168.4.52 port 5001
o    [  3]  0.0-10.0 sec  1.10 GBytes    942 Mbits/sec
o    [  3] 10.0-20.0 sec  1.09 GBytes    937 Mbits/sec

Sample server output:

o    ------------------------------------------------------------
o    Server listening on TCP port 5001
o    TCP window size:   256 KByte (default)
o    ------------------------------------------------------------
o    [  4] local 192.168.4.52 port 5001 connected with 192.168.4.118 port 36589
o    [  4]  0.0-19.4 sec  2.13 GBytes    941 Mbits/sec

Make a note of the bandwidth value.

Measure throughput with the data domain as the client

The test should now be run in reverse, using the data domain system in client mode.

Obtain the IP address of the other system networked to the data domain system.
1. If the other system is a data domain system, at the other data domain system command prompt type:
```
># net show settings
```
2. If the other system is a Windows or UNIX based computer, find the IP address using the Operating System specific instructions for that computers OS.
Make a note the IP address.
Run iperf in server mode on the other system.
1. If the other system is a data domain system, at the other data domain system command prompt, type:
```
# net iperf server
```
2. If the other system is not a data domain system, at the computer command prompt type:
```
# iperf -s
```
Run iperf in client mode on the data domain system. At the data domain system command prompt type:
```
# net iperf client  duration 60 interval 10
```
The test will complete in 60 seconds.