To mirror or not to mirror, and how

[davidbooker]

I am redeveloping a large international web site that may or may not need to have mirrors on multiple continents. Has anyone ever seen a good discussion of how best to decide this? The second part of the question is what's a reasonable method to use to seamlessly send visitors to the right mirror (without their needing to decide anything) while keeping their browser's address field still showing what they expect? Brownie points to anyone who can answer both!

[claus]

regarding redirect by language, i supplied a good link in msg #4 of this thread:

[webmasterworld.com...]

-there's a lot of ways of keeping the address field, from frames to internal redirects. I don't know any good discussions on when to mirror, so no points for me i guess

/claus

[davidbooker]

Claus,
So what ARE some ways of using internal redirects to keep the address field?

Nobody else out there has any ideas on WHETHER to mirror?

Cheers,
Dave

[claus]

Right, i'm gonna hit you with a link or two. Please don't think i'm rude or it's just an easy escape from a difficult question. Depending on your physical server setup there will be different things you can do. Plus this is complicated stuff.

First, you'll need to consult this document: [httpd.apache.org...]
(Apache 1.3 URL Rewriting Guide)

You might as well bookmark it right away, as it has tons of goodies in it.

Look at the section "Content Handling" to get a quick grasp of things. There's the internal method in which urls are substituted without being shown to the browser and there's the external method in which the browser urls are changed.
In bothe cases you serve document b when a is requested:

a) ~quux/foo.html
b) ~quux/bar.html

-the [R] flag being the only difference. Now, a bit further up the page you'll find "Archive Access Multiplexer" - this is redirects between different mirrors of a site (de, uk, com) depending on the value of REMOTE_HOST. It is external, so it will be seen, but for this purpose it doesn't matter - it's "traditional mirroring"

What you probably need is the solution under the headline "Dynamic Mirror" - this is applicable ie. if you have your mirrors on another domain. You might also want to check out the example: "Proxy Throughput Round-Robin" - this is a way to load balance a few servers, but if you have perl skills, you can do the redirection in the "lib.pl" script.

Then, of course, you might want to read the first message of this thread: [webmasterworld.com...] (and please don't be offended by the title "Newbie Cloaking Primer" - it's a very good explanation of what happens). Of course, this message suggests a method that is purely script-driven (without using mod_rewrite), and that can be done as well.

Finally, i'll have to provide this link as well: [httpd.apache.org...]
(Module mod_rewrite URL Rewriting Engine)

It's Apache documentation on the many directives and flags etc. you'll see employed in the "Apache 1.3 URL Rewriting Guide" (first link)

/claus

[claus]

i was a bit quick when writing the above, not that it's wrong, but this sentence:

>> this is applicable ie. if you have your mirrors on another domain

-might be rephrased as: "this is how you show content that physically is on another domain, keeping your domain in the address bar"¨(that is, your .fr or .de mirror will be shown at your .com address)

---

Now - can anyone offer davidbooker some good views on when to mirror and when not to mirror?

<bump>

/claus

[miles]

I am trying to figure out why you would want to use a mirror page in the first place. Unless you are trying to drum up some more business at the risk of getting pegged as a spammer.

Question one that depends on how good of a webmaster you are. If you can point the links to the best or most relivant section/url then you should have no problems with the seemless transfer from one site to another.

Question two you can use noframes pages and they will keep the same url while providing the information you want to display.

[davidbooker]

Why mirror? Because the site (and any other in Europe) takes too long in transit to view in Australia, S. America, Africa, Asia..... Or so it would seem. Is 8 seconds of loading acceptable? Is 3? How should I decide? And how much faster would a good fast server in Australia, lets say, make the load time? That's the kind of questions I've never seen discussed.

-David

[volatilegx]

IMHO 8 seconds is way to long. 3 is more acceptable.

If you expect to have visitors from every continent, then I would mirror. Apache's Mod_Rewrite will give you the ability to easily mirror.