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

Wed Jan 12 17:07:15 CET 2011

* andre999 (andr55 at laposte.net) wrote:
+> Olivier Thauvin a écrit :
+>> * andre999 (andr55 at laposte.net) wrote:
+>>> Michael Scherer a écrit :
+>>>>
+>> This is a selfish point of view, nothing is important except the result
+>> on your side.
+>
+> Sorry, but this can't be serious.
+> If a user is to download say a 4,7G DVD iso, it is 4,7G if the user uses  
+> one or 5 connexions, from one or 5 mirrors.
+> And if the 5 connexions go to 5 different mirrors, that is only 20% per  
+> mirror.
+> Globally, if the same files are downloaded, the same amount of data is  
+> downloaded.
+> What we are talking about here, from the user side, is downloading  
+> faster, if the capacity is _available_ on the network of mirrors.
+
+Exactly, it is seriously a selfish point of view as:
+- you're talking about users side, me both
+- IF the capacity, obviously no one really know the capacity of mirrors
+  except admin of them (and I am one of them).
+
+Moreover you're mixing "downloading on several server" and "downloading
+several time on one or more servers".
+
+> There are many mirrors which provide multiple connexions, with a very  
+> large bandwidth.  If users don't use the available connexions on these  
+> servers, other mirrors will be more heavily impacted.
+> So, as I said in another post on this thread, it is win-win for both  
+> users and mirrors.
+
+All mirrors provides multiple connection, otherwise they would serve
+only one client a time...
+
+And no, it is not win-win, I am trying to explain, munin statistics in
+hand, only the users think to win something. And you're ignoring my
+comment as mirror admin.
+
+> Think of it another way.
+> Scenerio 1)  Suppose at this moment the mirror network has 20% free  
+> capacity.  We download without multiple connections or multiple mirrors,  
+> without using this excess capacity.  In one hour we are still  
+> downloading, at a time when there is no free capacity.
+>
+> Scenerio 2) We download using multiple connexions and multiple mirrors,  
+> accelerating the downloads with the otherwise unused 20% free capacity.  
+> In one hour, most of our downloads are finished, thus leaving free  
+> capacity.
+>
+> Just who is served by scenerio 1 ?
+
+Mirrors, they are not serving only you and your 5 connections, they
+already serving 100 users other than just you !
+
+I cannot see how the mirror will give more bandwidth with 1 or 5
+connections. Except in the case each connection take same amount of
+bandwidth, then you're 5 part while other take one. And this is not a
+fair use of ressource.
+
+> The users that don't have access, or the mirrors that are overloaded ?
+>
+>> Of course, if in the case I don't blacklist mageia and deny download via
+>> http/ftp to save my mirror (d-c is already under heavy load).
+>>
+>> So, no, don't donwload several times from a mirror.
+>
+> The solution ?  If a mirror can't handle multiple connexions, restrict  
+> it in some way.  Many mirrors do.  Either all the time, or from time to  
+> time.  Or throttle the transfer speed.
+> Just do whatever works best for the mirror in question.
+> However let users use the capacity available.  Because it may not be  
+> available in one hour, or even 5 minutes.
+
+The problem is (maybe I am not clear) your 5 connections will get queue
+letting other people having to wait more to download their file, or
+getting "too many connections" error.
+
+Indeed, this maybe does not matter for you, except when you'll complain
+because the distribution cannot be download.
+
+>
+> Why not think globally ?
+
+I do, especially, I prefectly when http stop to reply, it stop to reply
+globally, for Mageia but also for Fedora / Ubuntu / Scientific Linux /
+Arklinux / Gentoo / ... and all other project hosted on mirrors.
+
+This is really a more global issue.
+
+I also think my mirror have first to serve my work, and time to time
+my colleague complain about slowdown cause by external downloader (eg
+YOU).
+
+
+Here my POV:
+1) I am mirror admin and get tired of abuse
+2) I am mirror manager for the distro
+
+a) According the fact doing this create an huge load on some mirrors,
+b) according we'll have to search mirror around the world and the distrib
+  size is already a problem
+c) according doing this can discourage people offering space and bandwidth
+  for us
+
+I am aginst such things.
+
+I cannot deny you to do this, but don't complain if no mirror agree to
+serve you.
+
+-- 
+
+Olivier Thauvin
+CNRS  -  LATMOS
+♖ ♘ ♗ ♕ ♔ ♗ ♘ ♖
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