TWiki Mirror [was: Oregon mirror is not up to date]

Jeremy Huntwork jhuntwork at linuxfromscratch.org
Sat Jul 10 06:15:40 PDT 2004


On Saturday 10 July 2004 02:55 am, Jeremy Utley wrote:
> On Fri, 2004-07-09 at 18:14, Jeremy Huntwork wrote:
> > On Thursday 08 July 2004 04:24 am, Jeroen Coumans wrote:
> > > Jeremy Huntwork said the following on 08-07-2004 01:07:
> > > > On Wednesday 07 July 2004 06:48 pm, Jeroen Coumans wrote:
> > > >>We're moving to round-robin DNS. This basically means that
> > > >> there will be a rotating pool of up-to-date mirrors to which a
> > > >> user is dynamically redirected. Mirrors will be automatically
> > > >> synchronized, or if not possible, automatically removed from
> > > >> the pool.
> >
> > Although I agree with keeping your pool of mirrors dynamically
> > up-to-date, is RR really what you want?  From what I've read, it
> > returns an IP address based on who's next in the pool.  That means
> > that a person say in Australia could easily get sent to a mirror in
> > New York.  Wouldn't it be better to send a user to a mirror based
> > on locality?  Or does the DNS you're planning to use incorporate
> > proximity as a deciding factor?
>
> Although this would be nice, unfortunately, I don't know of a way to
> do so.  RR-DNS works by having one hostname with multiple A records
> in DNS (essentially assigning more than one IP to an individual
> hostname).  In the zone file, it would look something like this:
>
> www.linuxfromscratch.org IN A 1.2.3.4
>                             A 5.6.7.8
>                             A 9.10.11.12
>
> The client requesting the IP for www.linuxfromscratch.org would get
> ALL responses, and would choose one, usually at random, but some
> resolver implementations would simply pick the first one from the
> list all the time - no way to avoid that.  It's not a perfect
> solution, by any means, but the user would always have the choice of
> picking a mirror of their own (I do this myself, always using my own
> mirror, right down to making an entry in my hosts file that makes
> www.linuxfromscratch.org resolve to my mirror).
>
> -J-

Actually, BIND shuffles the order and then returns all. (Alexander, my 
BIND server seems to shuffle every two digs...)  So the client will 
usually choose the first one it sees.

What about instead of using DNS to choose a mirror, you let belgarath 
redirect?  (People who already know what mirror they want to use can go 
straight there, but people visiting the home page at belgarath could 
get redirected based on locality.)  I'm not sure how this would work 
(yet) but it *should* be possible to see where a request is coming from 
and redirect appropriately.  (I know something like this must be 
possible, some international sites like google do it - of course 
whether that's done via DNS or no, I don't know.)

Check out:
http://httpd.apache.org/docs-2.0/misc/rewriteguide.html

-- 
Jeremy Huntwork
http://www.jenacon.net



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