How do CDNs work?

Question

I am new to webdev and would like to understand how CDNs work?

Specifically how do CDNs achieve performance in retrieving the content? Is the content stored on disk, in a database in binary format, or on disk but the location stored in the database?

How is the data kept in sync? Does the end user only push new/updated content to one location and the CDN takes care of synchronizing the content?

When is it wise to use a CDN and are there any other alternatives aside from storing the data on disk?

Answer 1

A content delivery network or content distribution network (CDN) is a globally distributed network of proxy servers deployed in multiple data centers.

CDNs are very useful for a multitude of reasons. For website owners who have visitors in multiple geographic locations, content will be delivered faster to these users as there is less distance to travel. CDN users also benefit from the ability to easily scale up and down much more easily due to traffic spikes. On average, 80% of a website consist of static resources therefore when using a CDN, there is much less load on the origin server.

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