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CDN not being reconised! - Printable Version

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CDN not being reconised! - Kye - 06-21-2011 12:01 AM

First of here is a copy of a test without CDN

http://www.webpagetest.org/result/110620_62_W6K3/

I then activated it, for 95% of the images on the page

http://www.webpagetest.org/result/110620_ZS_W735/

My score went from 92 to 96 however I still get AAABAF

Why does it not reconise the CDN on most of images on the page?

Also, the page loads SLOWER sometimes now that I have a CDN then before. (lucky test, had 6.2 seconds before)

I will say before anyone needs to look, both cdn1 and cdn2 are hosted on the same server but are split to trick browsers into fetching the images faster.

How do i get the tester to recognize the CDN, the browsers do and so open up lots of extra connections to get the content.

Note: Serve resources from a consistent URL (53/100) - I know it's bad, but it is a limitation of the CMS I am using.

Any help is much appreciated.


RE: CDN not being reconised! - pmeenan - 06-21-2011 12:09 AM

Domain sharding != CDN

A CDN will physically locate the files close to users around the globe. If your users all come from a small region close to your server then it doesn't make sense to use a CDN. Domain sharding is only really useful these days if you are serving a TON of content (or if you have logic that applies it only to older browsers) because most browsers will open 6 connections per domain anyway.

There is overhead for each new domain (in the form of a DNS lookup and time to establish the new connections) so it has to significantly increase parallelism to make up for it.


RE: CDN not being reconised! - Kye - 06-21-2011 12:15 AM

So is it not worth having the extra subdomains to serve the images?

The main reason I did it is because theres a huge amount of images on the site (not my choice!). And i was under the impression that tricking a CDN would make browsers download the content faster bu utilizing more connections instead of having to wait for some images to finish before the rest are downloaded.

All of the users I care about are in London (we only operate in that area) and the server is currently in Germany as my host is good, and writes most of the CMS.


RE: CDN not being reconised! - pmeenan - 06-21-2011 12:20 AM

It is unlikely that additional domains will help, even with a large number of images. It might try to download more in parallel but if the browser is using the existing 6 connections reasonably well without too much blocking it will usually be bandwidth constrained anyway. Just ignore the F for the CDN (yeah, hard to ignore a big red F, I'm trying to think of ways to express that a CDN is not always necessary).

The biggest issue on the site right now is the html5.js blocking the rest of the content on your page from loading. It's possible that the conditional tag is causing it to block loading (adding an empty conditional tag at the beginning of the html has shown to help with that: http://www.phpied.com/conditional-comments-block-downloads/ ).

Thanks,

-Pat


RE: CDN not being reconised! - Kye - 06-21-2011 12:35 AM

Ah well, turned it back off again. I'll finish writing the plugin and see if someone else can make use of it.

Thank you very much for the link though, that does solve one of the more annoying issues on the site.

I'll get back to finding other ways to make the site go faster.


RE: CDN not being reconised! - Bushido - 06-23-2011 05:44 PM

Instead of a big red F for CDN perhaps a simple yes or no for detected or not detected. Reason being you either have one or you don't and different pages will use it to a different degree.

People like A's, they don't come back for F's :-)

Kye, for starters get a proper doctype on there, "<!DOCTYPE html>" is not valid for any browser. You might also want to change your title tag a little, the words travel and parking sitewide will not help a plumbing site get more search visitors.


RE: CDN not being reconised! - Kye - 06-24-2011 08:53 PM

http://ejohn.org/blog/html5-doctype/

What is the doctype then? Everywhere says that HTML5 doctype is that.

And people do find us in searches because they want a plumber who doesn't charge travel time Wink