The main benefit of using a CDN such as Limelight Networks (via mydeo.com) is that your content is accessible much faster than if it was self-hosted. This is because, in addition to having your content stored globally on a network of high-speed servers interconnected by high-bandwidth connections (a “private internet”), it is also cached.
Why is it cached?
When you upload your content to us, you’re actually uploading it to a local network of redundant servers called ‘origin servers’. Depending on where you are in the world, the origin servers will change. When someone on the public internet requests your content, that file is then ‘copied’ (although, not physically) to the nearest endpoint that Limelight Networks has in relation to the person making the request of your content. This second copy is known as a ‘cached copy’, and it is for all intents and purposes a snapshot of your file at a particular point in time.
By caching your file for subsequent requests, considerable performance gains can be harnessed.
The period of time for which your file resides in cache is known as ‘TTL’, or ‘Time To Live’ – and that will be the subject of our next article coming soon.
Is that why a file I deleted is still accessible on the CDN?
Generally speaking, if you’ve deleted a file from either mydeo.com or your mydeo FTP account, and it is still accessible using it’s URL, then yes – caching is in effect. But don’t worry, your content will disappear off the network soon. If it’s an emergency, however, and you need the content to be removed quicker than allowing it to expire ‘naturally’, you can contact us and we can request a purge of the cached content on the network. This process generally takes 2-4 hours from the time the request is made, but in some circumstances can take up to 24 hours to complete.
