How can I test the bandwidth on my Linode?

You can certainly test the network throughput of your Linode, though the results will vary greatly depending on your network and any other external networks the traffic goes through.

Bandwidth vs throughput

First, as a bit of background, bandwidth is sometimes used synonymously with the term throughput, though there is a difference. Bandwidth is the theoretical limit of the network capacity. Think of bandwidth as the amount of water theoretically able to go through a particular segment of pipe and throughput as the amount of water that is actually able to go through the entire system of piping at a particular time. Because of this, bandwidth is relatively static and generally only changes when networking equipment is upgraded or modified. In fact, we can see the bandwidth of a Linode on that Pricing page, like you mentioned. Throughput, however, changes based on lots of factors, including the size of the data, amount of data, and the bandwidth and load of all networks that the data is traveling through.

Using iPerf

You can test the network throughput to or from your Linode by using a tool called iPerf. We have a great guide on using iPerf here: Network Throughput Testing with iPerf.

Essentially, you'll want to install iPerf on your Linode and another machine outside of our network. This could be your home machine, though for quick tests you might want to skip this step and use one of the public iPerf servers listed at iperf.cc.

If using a public iPef server, run the following on your Linode, replacing ping.online.net with the url of the server you want to test against:

iperf -c ping.online.net -d -t 30 -i 10

If using your own machine as well as your Linode, run the following commands:

On your Linode: iperf -s
On your external machine: iperf -c $linode-ip -d -t 30 -i 10, replacing $linode-ip with the IP address of your Linode.

These commands run a bidirectional test every 10 seconds for 30 seconds. You can adjust these settings as necessary.

Keep in mind, the speeds you see in iPerf will certainly be less than the total bandwidth of your Linode. That's completely expected!

It's a good idea to measure both bandwidth and latency. iperf 2.0.14a has latency measurements using --trip-times. It does required clock synchronization between the client and the server.

iperf 2.0.14 found here
iperf 2.0.14 man page here

Here is an example

[rjmcmahon@localhost iperf2-code]$ src/iperf -s -i 1
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  1] local 192.168.1.10%enp2s0 port 5001 connected with 192.168.1.62 port 47790 (MSS=1448) (trip-times) (sock=4) (peer 2.0.14-alpha)
[ ID] Interval        Transfer    Bandwidth    Burst Latency avg/min/max/stdev (cnt/size) inP NetPwr  Reads=Dist
[  1] 0.00-1.00 sec  1.09 GBytes  9.34 Gbits/sec  2.990/1.007/3.716/0.371 ms (8907/131083) 3.34 MByte 390539  18552=2380:2537:2636:2482:2250:2158:1919:2190
[  1] 1.00-2.00 sec  1.10 GBytes  9.41 Gbits/sec  3.001/2.322/3.675/0.348 ms (8979/131060) 3.37 MByte 392185  19320=2659:2821:2790:2622:2340:2166:1840:2082
[  1] 2.00-3.00 sec  1.10 GBytes  9.41 Gbits/sec  3.002/2.308/3.733/0.348 ms (8978/131077) 3.37 MByte 392060  18635=2447:2683:2540:2308:2152:2149:2096:2260
[  1] 3.00-4.00 sec  1.10 GBytes  9.41 Gbits/sec  3.003/2.321/3.710/0.348 ms (8979/131066) 3.37 MByte 391940  18625=2350:2641:2582:2355:2258:2250:2049:2140
[  1] 4.00-5.00 sec  1.10 GBytes  9.42 Gbits/sec  3.003/2.306/3.669/0.349 ms (8978/131084) 3.37 MByte 391956  19504=2550:2941:3029:2662:2300:2176:1927:1919
[  1] 5.00-6.00 sec  1.10 GBytes  9.41 Gbits/sec  2.971/2.260/3.670/0.364 ms (8979/131063) 3.33 MByte 396167  18766=2459:2647:2659:2370:2236:2194:2007:2194
[  1] 6.00-7.00 sec  1.10 GBytes  9.41 Gbits/sec  2.974/2.276/4.351/0.364 ms (8978/131081) 3.34 MByte 395705  19148=2553:2707:2801:2590:2360:2183:1865:2089
[  1] 7.00-8.00 sec  1.10 GBytes  9.41 Gbits/sec  2.972/2.295/3.864/0.363 ms (8979/131058) 3.34 MByte 395932  19108=2536:2840:2717:2537:2287:2095:1983:2113
[  1] 8.00-9.00 sec  1.10 GBytes  9.42 Gbits/sec  2.972/2.254/3.685/0.363 ms (8979/131071) 3.33 MByte 396009  19180=2533:2800:2773:2592:2309:2242:1884:2047
[  1] 9.00-10.00 sec  1.10 GBytes  9.41 Gbits/sec  2.971/2.253/3.673/0.364 ms (8978/131083) 3.33 MByte 396052  18993=2534:2694:2807:2435:2240:2188:1893:2202
[  1] 0.00-10.00 sec  11.0 GBytes  9.41 Gbits/sec  2.986/1.007/4.351/0.359 ms (89741/131072) 3.35 MByte 393842  189883=25004:27332:27334:24955:22734:21801:19483:21240

[rjmcmahon@localhost iperf2-code]$ src/iperf -c 192.168.1.10 -i 1 --trip-times -e
------------------------------------------------------------
Client connecting to 192.168.1.10, TCP port 5001 with pid 17357 (1 flows)
Write buffer size: 131072 Byte
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  1] local 192.168.1.62%enp2s0 port 47790 connected with 192.168.1.10 port 5001 (MSS=1448) (trip-times) (sock=3) (ct=0.36 ms)
[ ID] Interval        Transfer    Bandwidth       Write/Err  Rtry     Cwnd/RTT        NetPwr
[  1] 0.00-1.00 sec  1.09 GBytes  9.37 Gbits/sec  8937/0          0     1634K/1104 us  1060923
[  1] 1.00-2.00 sec  1.10 GBytes  9.42 Gbits/sec  8981/0          0     1634K/1097 us  1073070
[  1] 2.00-3.00 sec  1.10 GBytes  9.41 Gbits/sec  8978/0          0     1634K/1109 us  1061104
[  1] 3.00-4.00 sec  1.10 GBytes  9.41 Gbits/sec  8978/0          0     1634K/1118 us  1052562
[  1] 4.00-5.00 sec  1.10 GBytes  9.42 Gbits/sec  8979/0          0     1634K/1095 us  1074790
[  1] 5.00-6.00 sec  1.10 GBytes  9.41 Gbits/sec  8975/0          0     1634K/1128 us  1042882
[  1] 6.00-7.00 sec  1.10 GBytes  9.42 Gbits/sec  8979/0          0     1716K/1093 us  1076757
[  1] 7.00-8.00 sec  1.10 GBytes  9.42 Gbits/sec  8983/0          0     1800K/1115 us  1055982
[  1] 8.00-9.00 sec  1.09 GBytes  9.40 Gbits/sec  8969/0          0     1800K/1118 us  1051507
[  1] 9.00-10.00 sec  1.10 GBytes  9.42 Gbits/sec  8982/0          0     1800K/1082 us  1088067
[  1] 0.00-10.00 sec  11.0 GBytes  9.41 Gbits/sec  89743/0          0     1800K/1082 us  1087070

Anther way to think about things is in terms of cars, i.e. distance, speed and horsepower. Instead of throughput read the Transfer column. That's the amount of information in bytes moved over the interval. The actual speed of the transaction is the latency and not the throughput. In the above it took an average of 3 milliseconds to get a block of memory (131702 bytes) moved from client to server. The net power, here read on the server side, is about 3.37. There aren't really units for netpower but read it as a number where higher netpowers are better. Its a measure of throughput / latency or good / bad.

A paper by Leonard Kleinrock titled Internet congestion control using the power metric: Keep the pipe just full, but no fuller may help.