Do I need a CDN if I have Cloud Computing?

Over last year or so, the term Cloud Computing has been making headlines. There are several new entrants into the Cloud Computing industry. The idea is simple, you have all these computers or servers directly connected to the cloud (The Internet) and you have massive computing power at your fingertips. Companies like Rackspace, GoGrid, Amazon, and AT&T are all offering one form of Cloud Computing or another.

The services available from these companies range from simple “Cloud Storage”, to fully scalable virtual servers in the cloud.

When to use Cloud Computing

The great thing about these services is the instant setup and “unlimited scalability”. When you want a new website, with a few clicks of a mouse you bring up a new Linux or Windows box. They even make it easy for you by pre-installing services like SQL, Mail, and in some cases applications like Wowza or Windows Media streaming server.

The setup process is usually wizard driven and they take the guesswork out of setting up server software and services.

A couple of cloud-computing providers even partner with Content Delivery Networks (CDN) to offer Cloud Storage. Essentially you put your files in the cloud storage and they are on a CDN.

Sounds good, why do I even consider a CDN?

All of these services are on virtualized boxes and shared resources. They are not dedicated. The services are not fully managed either. You would be responsible for software updates, patches, licenses, etc; although you really shouldn’t ever be concerned about hardware or bandwidth. The idea behind cloud-computing is that you just pay more and they dedicate more resources to your servers.

If you have an existing data center or web servers, you may hesitate moving your web sites or web servers to a cloud-computing Provider. This may mean abandoning hardware and software you’ve already invested in. You may consider bringing up new servers in a cloud environment to reduce costs or gain flexibility.

If you have a lot of web sites it may make sense to consider a cloud provider versus a normal web host provider. You will have more control over your domains and depending on your provider you may be able to scale easier. Plus you would have full root access to the web servers to configure them however you want. It would be like a dedicated server package from a web host provider.

If you plan to use a cloud computing company in lieu of a CDN, thinking you can just build your own CDN within their cloud, think again! Start asking your cloud-computing vendor these questions: how many data centers are they in? What kind of peering arrangements do they have? What are their peek bandwidth capabilities/egress capabilities? Where in the world are they hosted? Will your servers be replicated everywhere around the world or just in the US, just in one data center? Are there more costs involved for Europe, Asia, or Australia delivery? What if you need streaming servers for videos, can they do that? What about mobile delivery? Do they offer token-based authentication? Pseudo Flash Streaming? What about encoding and transcoding? Does your cloud-computing vendor have any content management software or video? Do they support live video delivery? These are all questions to consider if you think you want to use a cloud-computing company instead of a CDN.

A tier 1 CDN like Limelight or Akamai will have thousands of servers to cache your content around the world. They will offer all those ancillary services related to content delivery. A CDN will support streaming and HTTP progressive downloads. They will probably have Adobe, Microsoft and Apple servers. A CDN will be able to support live events. On top of that you will be able to accelerate your whole site, with Akamai’s DSA or Limelight’s Limelight Site services. You are not limited to just videos with a CDN, any piece of content can be delivered via a CDN.

You will probably find that integrating a CDN is easier and less time consuming than bringing up new servers and maintaining them. In some cases with a CDN it may be as simple as pointing a CNAME to the CDN or just uploading your content to them.


Certainly, the pricing of cloud-computing is more attractive than a CDN. But you will need to figure out what your needs are and find the right combinations of services.

Mosso by Rackspace

  • $100/month
  • 50 GB of storage space
  • 500 GB of monthly bandwidth
  • 10,000 compute cycles. Compute cycles measure how much processing time your applications require on the Mosso cloud. 10,000 compute cycles are roughly equivalent to the monthly capacity of a server with a 2.8 GHz modern processor. per month
  • Prices go up from there.


  • $.19/hour of RAM (add more RAM, pay more) $136/month per 1GB of RAM plus
  • $.50/GB of transfer outbound
  • 10GB of storage included $.15/GB thereafter
  • Free Load Balancing with F5 load balancers

Amazon EC2:

  • $.10/hour up to $.80/hour for “On Demand”
  • $325 setup up to $2600 setup + $.03/hour up to $.24/hour for a “Reserved” server
  • $.10/GB on inbound traffic
  • $.10 to $.17/GB for outbound traffic
  • Storage is extra through the S3 service
  • Other services are extra

AT&T Synaptic Storage as a Service:

  • Pricing not disclosed

CDN PricingPricing for CDN service will vary greatly depending on what you want and where you get if from. With the Tier 1 CDNs expect a minimum commitment per month and to sign a 1-year contract. With a Tier 2 CDN like Level3, CDNetwork, Edgecast, etc, you may get a month-to-month contract and lower prices, but you may not get the same service either.

Pricing for CDNs will be anywhere from $.05/GB to $1.00 or more per GB depending on what you commit to. Keep in mind only the largest contracts in the hundreds of TBs to Petabytes will get down to the $.05/GB range. When you add on ancillary services, you will add to your monthly bill as well.

It appears that Rackspace wins on pricing, although as you add on more CPU Cycles and storage they may increase significantly. Rackspace is also known for their customer service, which will count for a lot. Amazon’s pricing seems convoluted and confusing, it looks cheap on the outside, but if you add up all your inbound/outbound, storage and class of service, their pricing isn’t too aggressive. Also, Amazon is not known for customer service at all. Getting a hold of tech support may be a chore. GoGrid’s pricing is very close to Rackspaces’ and their product seems top notch, also the free load balancing counts for a lot, so don’t count out GoGrid. Finally, AT&T has only just announced their cloud storage product. Their web site doesn’t disclose pricing. Good luck getting someone at AT&T on the phone that can help you understand their product.


If you’re looking at Cloud Computing to increase website performance, you may consider a CDN first. Examine why your site is under performing. Do you need more databases, do you need more mail servers? Do you need more domains? These are all reasons to get cloud computing. But if you have a lot of videos, music or software downloads or your pages are sluggish, then a CDN is the way to go!

Ideally, your best solution will be to use both a cloud-computing company and a CDN. This will give you optimal performance, flexibility, and reliability.

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DigitalMediaGuy (Mike Colburn)

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