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I'm trying to artficially slow down my servers network to reproduce bugs in some client software that only show up on high latency networks. I may be confusing bandwidth and latency here, but suffice it to say I want my network to be 90's slow.
I read the other questions on this site and found wondershaper, however its effects are mysterious to me. Here's a shell session with my commentary about what is confusing,
First i collect my baselines
~/git/wondershaper$ curl -s https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py | python -
Retrieving speedtest.net configuration...
Testing from Linode (xxx)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by Vorboss Limited (London) [0.92 km]: 9.165 ms
Testing download speed................................................................................
Download: 340.61 Mbit/s
Testing upload speed................................................................................................
Upload: 445.78 Mbit/s
Now I limit the upload bandwidth to 256Kbit/s
~/git/wondershaper$ sudo ./wondershaper -a eth0 -u 256
And run the speed test again
~/git/wondershaper$ curl -s https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py | python -
Retrieving speedtest.net configuration...
Testing from Linode (xxx)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by Vorboss Limited (London) [0.92 km]: 3.41 ms
Testing download speed................................................................................
Download: 18.89 Mbit/s
Testing upload speed................................................................................................
Upload: 0.55 Mbit/s
This time my download speed has reduced by an order of magnitude, and the upload is 550Kbit/s, not the requested 256. Now I clear the configuration and try just download limiting,
~/git/wondershaper$ sudo ./wondershaper -c -a eth0
~/git/wondershaper$ sudo ./wondershaper -a eth0 -d 256
~/git/wondershaper$ curl -s https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py | python -
Retrieving speedtest.net configuration...
Testing from Linode (xxx)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by Community Fibre Limited (London) [0.92 km]: 5.184 ms
Testing download speed................................................................................
Download: 0.13 Mbit/s
Testing upload speed................................................................................................
Upload: 55.38 Mbit/s
This time download is at 130Kbit/s, which is almost half what I requested. With upload it was almost double what I requested... The upload speed here is also much slower, and I didn't want that... Clear again and trying limited both up & down,
~/git/wondershaper$ sudo ./wondershaper -c -a eth0
~/git/wondershaper$ sudo ./wondershaper -a eth0 -d 256 -u 256
~/git/wondershaper$ curl -s https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py | python -
Retrieving speedtest.net configuration...
Testing from Linode (xxx)...
Retrieving speedtest.net server list...
Selecting best server based on ping...
Hosted by Community Fibre Limited (London) [0.92 km]: 4.4 ms
Testing download speed................................................................................
Download: 0.15 Mbit/s
Testing upload speed................................................................................................
Upload: 0.72 Mbit/s
Now i get 150Kbit/s down and 720Kbit/s up. Nothing near what I asked for.
What am I misunderstanding here?
HenryF1
Posted 2019-08-05T11:57:01.947
Reputation: 1