[announce] yum: parallel downloading

[Zdenek Pavlas]

Hi Glen,

> Why is the default three connections rather than one? Is a tripling
> of the number of connections to a mirror on a Fedora release day
> desirable?

$ grep maxconnections /var/cache/yum/*/metalink.xml
/var/cache/yum/fedora/metalink.xml:      <resources maxconnections="1">
/var/cache/yum/updates/metalink.xml:      <resources maxconnections="1">

Yum understands this.

> Consider that a large mirror site already sees concurrent connections
> in the multiple 10,000s.

Three connections limit is used when the above is not available
(e.g. a baseurl setup with just one mirror).  I don't mind lowering
it to just two, as that should work good enough in most cases.