ISO downloads with multiple mirrors for higher reliabilty, automatic checksum verification

[Anthony L. Bryan]

> Anthony L. Bryan wrote:
> > I've made Metalinks for a few FreeBSD ISOs:
> > 
> http://www.metalinker.org/samples/FreeBSD_6_2-BETA3-amd64-boot
only_iso.metal
> > ink
> 
> As these Metalinks are not officials, would it be possible to remove 
> ftp.fr.freebsd.org from these files ? I do not want to support nor 
> promote an "open standard" that encourage software to do parallel 
> segmented downloads.

Of course, François!
 
> I have several problems with segmented downloads. As software open 
> several connections (it may be several connections on a 
> single server or 
> single connections on several servers, the result is the 
> same), servers 
> will serve more connections and will have less memory usable per 
> connection. As one of the biggest problem on servers is 
> related to disks 
> IO optimizations, less memory may lead to smaller block reads 
> (and thus 
> higher disk load). Even if the server has enough memory, as 
> the file are 
> requested by segments, you are disabling on the server the ability to 
> fully optimize its disk requests. Last but not the least (and it does 
> not concern bittorent downloads, only servers), if you do not 
> download 
> at max speed, it means there is a _real_ bottleneck. It may be on the 
> server, it may be on the network but speeding up download by using 
> segmented downloads will not create bandwidth, you will just steal 
> bandwidth to other people.

While some people are using metalinks for segmented downloads, others are
not. Some people use them for the enhanced reliability of having extra links
to fall back on. I can not force download managers or metalink clients to
change how they have been behaving for years, but I can encourage them to be
respectful of server resources. Which is why I have been asking for
suggestions on how to improve things.

Can you think of some per transfer and per server options that would help
the situation?

Maybe something like for each transfer max connections and max servers and
for servers something like max connections and segment size?

(( Anthony Bryan
 )) Metalink [ http://www.metalinker.org ]