BitTorrent sucks
 

the stuffing out of my router. At least I guess the router (Netgear WGR614) is the choke point. Here is the situation:

I am downloading a CentOS DVD iso (actually it looks like two DVDs but more on that later) using Transmission 1.9.3 on a netbook running Ubuntu 10.04. The Internet connection is a 3 Mb DSL line which my test script shows to be running at its normal full speed. The BitTorrent client is downloading in the range of 240 - 270 MiB/s. And my desktop - also Ubuntu 10.04 is dog slow accessing the web - almost like a bad dialup connection.

That said... I routinely download NNTP at 350 MB/s or better with no significant impact on other machines on the network doing web browsing. I also use Internet Download Manager - a Windows utility - from within a VMWare virtual machine. It is a multi thread download tool and will pull all the throughput available from the DSL line. Again the router will provide bandwidth to requests from other machines.

I wonder if it is the 60 peer connections in BitTorrent which are causing the problem? The el-cheapo router does not provide much in the way of troubleshooting data. I am reluctant to reduce the number of allowed peers in mid download - not sure what that would do.

Another question... The torrent thinks it is 4.6 GB in size. Transmission tells me I have downloaded 2.8 GB at the moment. However, If I look at the downloaded files they add up to 4.6 GB. Is this some sort of new math? I see ...DVD-1of2.iso and ...DVD-2of2.iso so I hope there are two separate DVDs and I have not got two of the same thing downloading in parallel.

TIA,

Ken

All can be explained...

The slow connection for computers on the network is normal when using bittorrent, I think this is because it constantly uploads data very often. I don't know if I speak for everyone, but this seems to happen with bittorent with any client on any OS, so I'm pretty sure I'm right.

As for the size difference, it is because bittorrent creates large files as place-holders, and downloads the data into them. This is because it is a non-linear download, it can be downloading the beginning or the end of the file (or middle, etc) ... how could you create such a file if you didn't first make an empty file of the same size ? You can't.

Thanks H_TeXMeX_H - an excellent explanation. I don't use torrents very often so I guess I had not noticed the issue before. As for the allocate the file first technique - reminds me of a funny work experience I had several years ago at a Fortune 500 company (which will remain nameless).

The manager came to me and asked "how much trouble will I be in if I fire Raul?" It seems that Raul was a contractor at one of the company's facilities and he was running some sort of supply chain application which tracked commercial items which the engineering folks had qualified for use in the nuclear plant. His "system" produced various status reports concerning the status of various items in the backlog to be processed. He seemed to be the only one to have any knowledge of the system.

I found that the database back end was Dataease or Dataflex or something like that. Nothing I or any of the corporate IT staff had ever used. The manager was getting quite concerned about Raul or the lack therof and what would happen to the tracking system which contained the results of all of his engineers' work. "What will happen if the police come and take Raul away in handcuffs?" Raul wanted to license "his" system to us.

I started digging into the old contracts regarding the project which created this mess - paper records in a musty warehouse! Raul or his company had leased us a 4800 bps modem to access something and he seems to have come with the deal. He had been on site for almost 10 years. Along the way he built the alleged system.

So I got hired a consultant who spoke the particular database. I called my buddy who was the administrator of the Banyan server which hosted the system and borrowed a backup tape. I had it loaded on a test server. There were several LARGE (for those days) 20 MB files which I guessed contained the data we were looking for. I turned it over to the consultant. He told me that the files were all empty - just pre-allocations. The "system" contained nothing. I guess Raul was producing the reports by hand.

Low and behold a few weeks later I heard from the manager that Raul had been arrested and extradited to Florida - something about a bunch of dummy corporations he was involved with. Sort of the business equivalent to pre-allocated empty files :D

Thanks again,

Ken

Ok, you seem not to know what Mbit is vs MByte, since 3Mb/s (small b means bit not byte), is nowhere near 240 MB/s, so, this is quite impossible.
Secondly, lateron you say you download with even more speed, namely 350MB/sec..

All in all very very impressive for a DSL line with just 3Mb/s!! :D

So what is your real speed? (Mb = Mbit, MB = MegaByte)

Anyway, back on track about the slowdown.. this is not to blame on BitTorrent itself. It's about your settings for it.
I have a 60Mb/s (that is arround 7MB/s) connection here at home, and i get depending on the seeders available in relation to the leechers, full speed often.
(it's more rule, than exception for that manner)

even when i had a DSL line (20Mb/s). I got quite a good ratio, my top speed for everything was max. 11Mbit/s (that's because i was to far away from the Telco center, thus dropping my speed significantly overal.)
but again with torrents, i would regularly got 11Mbit/s on that line.

I guess you need to check your settings. (the max speed for uploads, the max for downloads, max connections per torrent, max upload slots, all those things) Also make sure, your upstream portnumber is open in your firewall, otherwise the tracker cannot find you.

Well pardon my typo 350 - 360 kB/s is my normal speed. Not sure what the torrent client was reporting - I will have to look closer next time I fire it up. I focused on the number not the unit of measure.

As it happens there seems to be some issue with my ISP this afternoon/evening - I am just about to call them. My ftp download/upload script is reporting 160 - 280 kB/s now. So that could at least answer why the torrent was not running at full speed. As to the sluggish performance of other machines on the web - undecided at this point.