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LAN benchmark

There are many reasons for measuring LAN speed; one of them is when there's a central server, like in LTSP, and the network speed is mixed, i.e. the server ⇔ switch connection is 1 Gbits/sec, while at least some of the clients connect to the switch with 100 Mbits/sec connections. In that case, the flow control issue might reduce the server ⇔ switch connection to 100 Mbits/sec as well!

To benchmark your LAN with Epoptes, first verify that you have iperf installed in both your server and your clients.

Second, open a terminal on your server, and run:
iperf -s -xS

"-s" means to run in server mode, and "-xS" to exclude the Settings report, in order to have less output.

Third, from the Epoptes UI, select all the clients, and press the Execute command button in the toorbar. Use this command:
sudo iperf -c server -r

"-c server" means to run in client mode and to connect to "server", the special DNS name that LTSP clients know their LTSP server as. If you're not using LTSP, put your server IP there instead.
"-r" means to do a bidirectional test individually. So, two parts of output will be shown; the first one will correspond to data transferred from the clients to the server (94.0 and 93.9 in the example below). We usually don't care about that part, but for the next part, which shows data transferred from the server to the clients (92.6 and 62.5 in the example below). For optimal LTSP experience, ensure that all numbers in the second part are > 50 Mbits/sec, and that their sum is > 500 Mbits/sec.

Sample output for two clients:
$ iperf -s -xS
[  4] local 10.160.200.11 port 5001 connected with 10.160.200.242 port 32833
[  5] local 10.160.200.11 port 5001 connected with 10.160.200.155 port 43712
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec   112 MBytes  94.0 Mbits/sec
[  5]  0.0-10.0 sec   112 MBytes  93.9 Mbits/sec
[  4] local 10.160.200.11 port 48337 connected with 10.160.200.242 port 5001
[  5] local 10.160.200.11 port 45048 connected with 10.160.200.155 port 5001
[  5]  0.0-10.0 sec   110 MBytes  92.6 Mbits/sec
[  4]  0.0-10.0 sec  74.8 MBytes  62.5 Mbits/sec
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