Topic: Why do external users experience slow download speeds from my server?

[holck]

I host a couple of large multimedia files on my server, but external users find it quite slow to download them. One user has just experienced 2 hours of download time for a 700 MB file from my server, compared to the same user downloading a 200 MB file from another server in just 1 minute.

Running speedtest-cli on my server shows:

Code: [Select]

Retrieving speedtest.net configuration...
Retrieving speedtest.net server list...
Testing from SEAS-NVE Holding A/S (5.103.132.90)...
Selecting best server based on ping...
Hosted by Comendo A/S (Gladsaxe) [40.35 km]: 37.67 ms
Testing download speed........................................
Download: 51.84 Mbits/s
Testing upload speed..................................................
Upload: 18.48 Mbits/s
This could of course be better, but 18 Mbits/s for a 700 MB file should give a download time of just 5 minutes. The server is no way heavily loaded.

Any ideas or suggestions?

Jesper, Denmark

[CharlieBrady]

There are many possible reasons. The most likely IMO is some packet loss between your server and wherever they are trying to download from.

Traffic congestion is a complicated problem. It can take a long time to drive from point A to point B on busy city streets, without there being any problem or delay getting out of your own driveway. IOW, this issue might have nothing to do with your SME server.

[mmccarn]

Any ideas or suggestions?

How many ISPs are there between your server and your user?  Do you get the same slow download speed if you go to a nearby network (friend's house, wifi hotspot) and download the same file?

Your ISP or your user's ISP may be throttling bandwidth for multimedia files.  I don't know how you would prove this - maybe you could give him several files of different sizes, and see if the overall speed changes dramatically when the file exceeds a certain size (is the overall throughput the same on 10Mb, 50Mb, 100Mb and 700Mb files?) or a certain file name structure (maybe .mpg or .avi files download slower than .dbf files?)

The download may be using an inefficient protocol - can you give the user a different download method, in order to test? (If he's using FTP now, give him an HTTP address; if he's using HTTP, give him an FTP link; if he's using webdav, give him a "plain" HTTP URL; if he's using a VPN, give him a straight HTTP or FTP address; if he's using a webapp like owncloud, give him a direct HTTP or FTP link).

There could be a problem with network settings - if you have an ADSL modem enforcing a packet size of 1492 bytes, you might get better performance by hard-coding your SME server packet size to match as described here (I have no idea if this would affect overall download speed -- it just seems like a possibility).

If none of the above steps suggests a cause or solution, you could setup an alternative host for the file in question (an appliance with a built-in FTP server, a windows box running an FTP server, or another non-SME linux box) and see if the download speed improves.

[holck]

Thank you very much for all your advice. In my first post I didn't mention that I actually my ISP for 50 Mbit/sec, both upload and download. And as I didn't measure more than around 20 Mbit/sec outbound, I managed to get my ISP to look at it. They came and changed a cable, and now I do get 50 Mbit/sec outbound. And apparently, this has helped a lot more than a 150% improvement - the speeds my users experience are much higher now.

So probably it has been some hardware issue in my fibre-box or fibre-connection.