> From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of
> Jonathan Rochkind
> Sent: Thursday, April 02, 2009 10:53 AM
> To: [log in to unmask]
> Subject: [CODE4LIB] points of failure (was Re: [CODE4LIB] resolution
> and identification )
> 
> Isn't there always a single point of failure if you are expecting to be
> able to resolve an http URI via the HTTP protocol?
> 
> Whether it's purl.org or not, there's always a single point of failure
> on a given http URI that you expect to resolve via HTTP, the entity
> operating the web server at the specified address. Right?

I think the answer lies in DNS.  Even though you have a single DNS name
requests could be redirected to one of multiple servers, called a server
farm.  I believe this is how many large sites, like Google, operate.  So
even if a single server fails the load balancer sends requests to other
servers.  Even OCLC does this.

> Now, if you have a collection of disparate http URIs, you have _many_
> points of failure in that collection. Any entity goes down or ceases to
> exist, and the http URIs that resolved to that entity's web server will
> stop working.

I think this also gets back to DNS.  Even though you have a single DNS
name requests could be redirected to servers outside the original request
domain.  So you could have distributed servers under many different domain
names.


Andy.