Test Internet Speed from the Command Line

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Test Internet Speed from the Command Line

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speedtest-netMatt Martez has kindly created and shared a Python script for interacting with speedtest.net for testing bandwidth to the internet from the command line. This is a great script which only has the dependency of Python – something which is available on most Linux distributions.

Grab the script with wget to the server you wish to test. Remember, this is to test the bandwidth to servers which are publically available on the internet – this does not test your internal server to server communication. See Iperf for details on testing LAN bandwidth.

Add the execute permission:

And that’s all you need to start your first speed test! Run the speedtest-cli with the –simple switch to start your first basic speed test. The script will automatically choose the best server based on your location.

You can use the –help switch to see all the options you have with the tool.


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Testing network speed with Iperf

Category : How-to

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iperfIperf is an Open source network bandwidth testing application, available on Linux, Windows and Unix. Iperf can be used in two modes, client and server. The server runs on the remote host and listens for connections from the client. The client is where you issue the bandwidth test parameters, and connect to a remote server.

You can install Iperf using apt-get on ubuntu.

Once installed, on the remote host run Iperf in client mode. If you wish to run the server in daemon mode, add -D to the command.

Iperf has many configurable options for testing network throughput. For our test, we will use TCP connections to a remote server at IP 10.1.1.50. The test will use 4 threads, each sending data and the test will be performed in both directions.

The result will look similar to the below output. This example shows a total throughput of 9.42 Gbits/ second in one direction and 11.9 Gbits/ second in the other direction. As the results can fluctuate depending on the load of the server, or how congested the network is between the servers, it’s best to run each test 3 – 4 times at different times of the day and take an average.

For more test parameters see our Iperf cheat sheet.


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Iperf cheat sheet

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iperfIperf is an Open source network bandwidth testing application, available on Linux, Windows and Unix. Iperf can be used in two modes, client and server. The server runs on the remote host and listens for connections from the client. The client is where you issue the bandwidth test parameters, and connect to a remote server.

Install Iperf on Ubuntu

You can use apt-get install to install Iperf in Ubuntu.

Start server

To start Iperf in server mode, use the below command.

Start server in daemon mode

Running the server without daemon mode keeps the process running in the terminal. Use the -D switch to run it as a daemon in the background.

Connecting to server from client

Iperf needs to run on the local host in client mode, as well as in server mode on the remote host. To connect to the remote host, add it’s IP address after the -c switch.

Bi-directional simultaneous (test the speed both ways at the same time)

Use the -d switch to test in the network bandwidth in both directions. This will perform two tests; one from local host to remote host, and another from the remote host to the local host.

 

Bi-directional  (test the speed both one after another)

Use the -r switch to test in the network bandwidth in both directions. This is similar to -d except the tests will be performed in sequence; first from local host to remote host, and another from the remote host to the local host.

Change the window size

The TCP window size can be changed using the -w switch followed by the number of bytes to use. the below example shows a window size of 2KB. This can be used on either the server or the client.

Change the port

You must use the same port on both the client and the server for the two processes to communicate with each other. Use the -p switch followed by the port number to use on both the local and remote host.

Change the test duration

The default test duration of Iperf is 10 seconds. You can override the default with the -t switch followed by the time in seconds the test should last.

UDP instead of TCP

The default protocol for Iperf to use is TCP. You can change this to UDP with the -u switch. You will need to run both the client and server in UDP mode to perform the tests.

The result will have an extra metric for the packet loss which should be as low as possible, otherwise the packets will have to be re-transmitted using more bandwidth.

Run multiple threads

Iperf can spawn multiple threads to simultaneously send and receive data. Use the -P switch followed by the number of threads to use.

Check the version of Iperf

Use the -v switch to see the version of Iperf you have installed.

See the full list of arguments

Use the -h switch to see the full list of arguments supported by Iperf.

 

Let me know in the comments if you think anything is missing.


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Limit backup I/O bandwidth

Category : How-to

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proxmox_logoWhen backing up in Proxmox, especially on the lower end of the server market, the backup process can cause your system to almost grind to a halt. Luckily, there is a config change which we can make to limit the bandwidth of the backup process to make sure there is sufficient bandwidth for everything else.

The setting cannot be changed using the web gui, you must log into your Proxmox server using SSH. Once you have logged in, open the config file:

Find the line which contains bwlimit, remove the hash and append the value of KB/s which you would like the backup limiting to. The below example limits the backup process to 40000 KB/s.

To calculate how many KB/s you need will take trial and error to see what affect speeds have on your system. Something which is helpful however, is converting MBs (Megabytes) into KB/s (Kilobytes). The formula is simple – just multiply the MB value by 1024 as there are 1024 KB in a MB.

If you want a transfer speed of 10 MB/s you would use a bwlimit value of 10240 as the below example shows.