[Mageia-dev] Proposal for Mageia: implement bitorrent protocol to allow updates download

andre999 andr55 at laposte.net
Wed Jan 12 11:06:10 CET 2011

Romain d'Alverny a écrit :
> On Wed, Jan 12, 2011 at 04:29, Michael Scherer<misc at zarb.org>  wrote:
>> Le mardi 11 janvier 2011 à 21:45 -0500, andre999 a écrit :
>>> Some suggestions for faster downloads without bittorrent.
>>> 1) use aria2c (or a similar application), which uses multiple
>>> connections, defaulting to 5, and allows multiple mirrors.
>>> By default it starts by allocating space for the file to be downloaded,
>>> which allows non-sequential downloading of the file, facilitating faster
>>> downloading from multiple sites.
>>> 2) use mirrors which allow multiple connexions.
>>> (Of course, with download software that takes advantage of this.)
>>> 3) use multiple mirrors.
>>> (Again, according to download software.)
>> Theses 3 suggestions basically put X time the load of the mirror for
>> each client. ( or on more mirror, for that matters ).
> However, if 1) was to open 5 connections on 5 distinct servers, that
> would make more sense, no?

Another way to look at the question :
If 1000 people are downloading from mirrors allowing a total of 2000 
connexions, if no-one uses multiple connexions, then 1000 connexions are 
wasted.  These unused connexions would likely be from faster mirrors.

The advantage of an application like aria2c, is that it detects 
automatically the speed of whatever the connexions are available from 
the urls (mirrors) specified, and chooses the fastest connexions.
Thus downloading at an optimal speed for the user.
At the same time, it makes the best use of the resources available, 
since the slowest connexions won't be used.  Thus relieving slower mirrors.
(Considering direct downloads, not options like P2P.)
Of course each user will have their own set of fastest connexions, 
depending on their location.  A user in Australia would have different 
connexions from someone in France, or here in Canada.
So in my view, the approach of aria2c is a win/win for both users and 

With aria2c, 3 mirrors which support a total of 5 connexions gives me 
optimal speed.  (The limit being the speed of my computer.)

> But then I'm not sure there is so much more value than using a P2P protocol.

P2P is great if one has (essentially) unlimited bandwidth, and many 
others are downloading at more or less the same time, and accessible to 
the Internet when you are downloading.
And it does relieve bandwidth from the mirrors.

But it's not as good for bandwidth limited users (which included many of 
us), or those downloading at a time when not many corresponding P2P 
downloaders are available.
(I knew someone who had a surprise 100$ plus surcharge due to P2P 
uploading, before understanding the bandwidth usage factor.)

An aria2c type solution doesn't require any cooperation from mirrors. 
Although resource-limited mirrors should protect themselves from this 
approach, to remain readily accessible.
I'm not sure what is required (from Mageia) for P2P, but it could be 
worth considering.

another 2 cents :)

> Romain


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