Ask HN: Tools for Debugging Network Bottlenecks? | Hacker News Reader

Ask HN: Tools for Debugging Network Bottlenecks?

1 pointvsroy3 comments

I've recently been having to transfer lots of files from place A to B. For example Hetzner => another cloud provider.

Anyways, I've realized I have no good way to answer questions like: "My download speed dropped to 0, is Hetzner throttling my bandwidth, or is it <other cloud provider>"?

Or, Hetzner claims I get up to 1GB/s network speed, but in practice I only get 13 MiB/s out of their cloud. Is the issue with them, or with the software I'm using to download, or with my computer?

So HN, what are the tools you use to debug network connections / data transfer jobs?

Mostly, I notice that I have never even got close to the promised 1GiB/s Hetzner bandwith when trying to download data.

View on HN

Based on the information provided, kinda difficult to assertain, as quite a few unknowns.

Per description, sounds like when transfering from A to B, what is happening is 1) downloading from A to computer, then 2) uploading from computer to B.

(vs. logging into Hetzner and initiating a direct transfer from Hetzner to another cloud provider, which may or may not be allowed by the Hetzner account).

Basic recomended step would be to find a 'internet speed test' site and test speeds from computer to A, and from computer to B.

Alternatively, if transfering directly between Hetzner and other provder, try using the internet speed test site from Hetzner account to where ever trying to transfer to. That would rule out the issue being with Hetzner. (assuming Hetzner account doesn't have a 'transfer only during non-peak hours' and/or other transfer limiting policies)

After that, would depend how internet connection is provided & local network & computer hardware/setup.

aka some ideas:

network card is 10mb network card, so will never be able to get speeds beyond the theoretical 10mb hardware limit.

Internet account maximum speed is 10mb.

Some internet accounts impose speed limits based on time of day.

Some accounts only permit uploads during non-peak hours.

Some connections, from an internet service providers view point, are 'shared bandwidth' accounts, so that more people connected, the more the available bandwidth is split between other users.

... etc ...

I'm hosting an open-source S3 (SeaweedFS) on hetzner, and I'm doing a direct download from hetzner => the other cloud provider.

I'm not aware of speed test sites that allow you to select the location (i.e doing a speed test from cloud provider A to Hetzner).

I'll look into what's going on by running some CLI speed tests on hetzner.

note: some providers require the following 'tests/checks' be handled by the provider support center, and NOT by the customer/customer account.

iftop provides traceroute / MTR information. which may show where the 'slow down' is (may not be because of Hetzner or the receiving cloud provider).

wget -O /dev/null 100mbsized.test.file

iperf & iperf3 allows for active measurements of the maxpossibile bandwidth with support for tuning various parameters related to timing, buffers and protocols. this would allow for changing/tuning sysctl.conf internet settings as appropriate. iperf/iperf 3 server on herzer and client on other cloud provider.

Reply on news.ycombinator.com