On Jan 20, 2009, at 7:40 PM, Adrian Chadd wrote:
On Tue, Jan 20, 2009, Patrick W. Gilmore wrote:
Define "cached".
For instance, most of the video today (which apparently had 12 zeros
in the bits per second number) was "cached", if you ask the CDNs
serving it.
Sounds to me like that is significant, no matter how big your network
is.
If, for example, Google's current generation of YouTube content
serving
wasn't 100% uncachable by design, Squid caches would probably be
saving a stupid amount of bandwidth for those of you who are using it.
People rolling Squid + 'magic adrian rules to rewrite Youtube URLs
so they don't suck' report upwards of 80% byte hit rates on -just-
the Youtube content, because people view the same bloody popular
videos over and over again. Thats 80% of a couple hundred megabits
for a couple groups in Brazil, and that translates to mega dollars
to them.
There's no reason to doubt this wouldn't be the case even in Europe
and North America for forward caches put in exactly the right spot
to see exactly the right number of people.
I tried talking to Google about this. Those I spoke to went from
enthusiastic one month to "sorry, been told this won't happen!"
the next month. Which is sad really; the people who keep coming
to me and asking about caching all those things you funny CDNs are
pushing out are those who are on things like satellite links, or
in eastern europe / south america, where the -infrastructure-
is still lacking. They're the ones blocking facebook, youtube,
etc, because of the amount of bandwidth used by just those sites. :)
I do not work for GOOG or YouTube, I do not know why they do what they
do. However, it is trivial to think up perfectly valid reasons for
Google to intentionally break caches on YouTube content (e.g. paid
advertising per download).
Doesn't matter if you have small links or no infrastructure or
whatever. Google has ever right, moral & legal, to serve content as
they please. They are providing the content for free, but they want
to do it on their own terms. Seems perfectly reasonable to me. Do
you disagree?
Sure the situation sux, but life is not fair.
As for CDNs, most do not do anything to the content they serve. A
content provider makes the content and hands it to the CDNs, which
serves the content. the CDN does not own, create, or modify the
content. (There might be edge cases, but we are talking generalities
here.) You see "funny" stuff, talk to the content owner, not the CDN.
(And I know about the various generations of Google content boxes
out there
and have heard stories from people who have and are trialling them.
Thats great if you're a service provider, and sucks if you're not well
connected to a service provider. Like, say, schools in Australia
trying
to run a class with 30-40 odd computers hitting Google maps at once.
tsk.)
Google is not the only company which will put caches into any provider
- or school (which is really just a special case provider) - with
enough traffic. A school with 30 machines probably would not
qualify. This is not being mean, this is just being rational. No way
those 30 machines save the company enough money to pay for the caches.
Again, sux, but that's life. I'd love to hear your solution - besides
writing "magic" into squid to intentionally break or alter (some would
use much harsher language) content you do not own. Content others are
providing for free.
--
TTFN,
patrick