Question

I’m using Amazom CloudFront as CDN and we may have to change between two systems according to situation.

Here’s what I need to be prepared for –

1. How much time will CDN take to resolve the new address every time (new system, old system)? The same time it takes the domain to propagate?
2. What about the cache it collected before changing?

I’m reading this article http://docs.amazonwebservices.com/AmazonCloudFront/latest/DeveloperGuide/HowToUpdateDistribution.html

It would be much better if someone shared his/her experience.

Answer 1

When you setup a new container on any CDN you are using their domains which are already propagated across the world. If you plan to use your own domain instead of theirs for example cdn.yourdomain.com or static01.yourdomain.com etc then standard propagate time comes into play.

What your find with CDNs is once you upload your files to the server it takes some times to “Spread” replicate your files on all there networks so for example say their main server is in america those accessing the files from UK will download from America and not a local server until all files have been cloned across their network, it takes from a few mins to a few hours depending on how many files and the sizes, the good thing is everyone can use those files with no delay but for full speed advantage it takes a little time.

As far as Cache its pretty straight forward you set a TTL expire on the containers which means they get cached and so on. Personally I use a 72 hour TTL on mine and is favored by Google and other search engines.

Hope this helps.