Cloud Files with Limelight Networks

Cloud Files is a new product offering from Rackspace/Mosso that is an inexpensive, scalable, dyanmic storage system.  We’ve partnered with Limelight Networks’ Content Delivery Service to bring you an incredibly easy way to publish your content over a world-class, industry leading CDN.

The core storage system is designed to provide a safe, secure, automatically re-sizing, and network accessible way for you to store your data.  You can store files ranging in size from a single byte up to 5 gigabytes and you can store as much as you want and only pay for what you use.  With Cloud Files there is no over-buying/under-utilizing storage space.  All data is secure and private and only accessible to that user account.  This is a great solution for storing system backups, copies of your digital media such as photos and videos, or as a storage system available to multiple computers.

By combining the core storage system with Limelight Networks’ CDN, you now have an easy way to distribute your data to everyone.  Limelight Networks has 18 edge locations over the globe with media-grade optical networks connecting them.  They provide CDN service to over 1300 businesses(1) who rely on their network to be performant and continuously available.  Our partnership with them is not a one-off solution; when you publish content through them it is distributed across their entire infrastructure just like all of their other customers.

  • Effortless: Non-developers have a simple web-interface that can be used to quickly and easily upload data and enable CDN access.  Users can, within minutes, sign up for Cloud Files, create a Container, upload a file and publish that Container’s content through the CDN.  This is great way to share out large video files with friends and family rather than trying to email large files to multiple recipients.  If you are a developer, we have a simple ReST web service and language-speicifc API’s in PHP, Python, Java, and C#/.NET.  All of the API’s are easy to use and provide documented examples to help you get started quickly.  They provide full support for managing your content in Cloud Files and publishing that content over the CDN.
  • Affordable: Storage starts at .15 cents/gigabyte and bandwidth costs start at .22 cents/gigabyte.  You only pay for what you use and the cost decreases as your usage increases!  There are no additional costs to publish your content behind the CDN either.  In addition to storage and bandwidth, there are also some nominal transaction costs.  Check out our pricing page for more information []
  • Redundant: The storage system has been designed to be highly available and fault tolerant.  We store 3 full copies of your data on 3 separate storage nodes, but we only charge you for one copy ;-).  Storage nodes are grouped in logical Zones within our datacenters.  Zones are connected to redundant internet backbone providers and reside on redundant power supplies and generators.  If you publish your content behind the CDN, that also provides an additional layer of data redundancy.
  • Secure: All uploads/downloads of data to the Cloud Files storage system is performed over SSL.  Requests against the storage system are only allowed if they contain a valid authentication token.  Authorization tokens are granted when a user successfully authenticates to the Mosso Authentication Service.  Authorization tokens are “session” tokens and expire over time requiring the user to re-authenticate periodically.

How it works
In the Mosso web-interface, it’s as simple as creating a Container (the storage compartment for your data), upload your Objects (the files you want to serve over CDN), and mark the Container as “public”.  The Container is then assigned a unique URL that you can combine with your Object names to embed in web pages, email messages, blog posts, etc.  For example, you could upload all of your family photos to a Container called “images”.  When you publish that Container, it will be assigned a unique URL like, “”.  You could then share out a link to one of your photos like “”.  When that link is accessed, the photo is served from the CDN; it’s that simple!

When that URL is accessed, the FQDN “” resolves to Limelight Networks’ CDN.  When they see the request for “c1234/IMG_3432.jpg”, they immediately serve the content from their cache if it exists.  If the photo doesn’t exist in their cache, the call back to Cloud Files for that Object and then serve it and cache it for the next request.  Data is cached in the CDN for a configurable amount of time (the default is 1 day).

When the CDN fetches the object for the first time, it is cached at an edge location that is geographically the closest to the requester.  As that file is requested from other geographic locations, the CDN propagates that file to other edge locations so that users are always accessing the file from the closest geographic location to them.  This is the magic that a true CDN provides.  Content is served to users from the closest edge location reducing latency and speeding up the end-user’s experience.

Once you CDN-enable a Container, any new Objects you upload to that Container are also available for access over the CDN just like the example above.  There is no complicated “access control list” that needs to be set on each Object you upload or re-setting the “public” attribute.

If at some point you no longer want your content accessible over the CDN, you can mark the Container as “private”.  Any data currently cached in the CDN will continue to be served, but when the CDN cache expires, the data will not be re-fetched/cached from Cloud Files.

What about CNAMES?  I don’t want to use !
A request we anticipate some users will want will be the ability to provide a custom name for the CND URL.  For instance, you might not want to use “” but would rather use a name in your own domain such as “” in your web sites.   Since this is not currently a supported feature of Cloud Files, we’d like to suggest an alternate way for you to use your own custom domain with Cloud Files.
You can use a custom URL in your own domain by using a concept called URL re-writing.  So let’s say you CDN-enable a Cloud Files Container and it is assigned “”.  Most popular web servers support a feature called URL re-writing that can be configured so that a request for “” is actually redirected to “”.  With this re-writing scheme, a request to an image would be automatically redirected to the Container’s CDN URL which in turn is served by the CDN.  Anyone familiar with the Apache mod_rewrite module could use something like this:

RewriteEngine On
RewriteRule ^*)$ [R,L]

So with this basic technique, you are in full control of how visitors access the content you publish with the Cloud Files CDN.  This technique can be used to capture web log hits, restrict access to specific users, or direct hits back to your local web server if you decided not to use Cloud Files CDN.

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  1. Wouldn’t this approach completely, or at least partially, negate the use of a CDN? In order to use this approach all requests for CDN-served content must first be made to your own, non-geographically-diverse web servers, and then a second request to the CDN must be made. So while the content ultimately comes from the CDN, the user has to make double the requests, and there is a point of failure on your web servers that are serving the redirect.

    Are there any plans on making scenarios like this easier to accomplish directly through Cloud Files?

  2. Hi John,

    You are absolutely correct. The URL re-writing suggestion is not a perfect solution but rather a short-term technique until we offer full CNAME support. We are working with Limelight Networks to add full support for CNAME and we hope to have that functionality soon. In the meantime, customers who are adamant about using their own domain name could use URL re-writing for now.

    We’ll keep our blog updated as we continue to add new features to Cloud Files.

  3. We are working with Limelight Networks to add full support for CNAME and we hope to have that functionality soon.

    very good to hear.

    could i also ask, do have any plans to support directories / subdirectories?

    would quite like to be able to drop an entire s3 folder structure into mosso, re-point a cname and have everything carry on working.


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