Deconstructing the Cloud

Sprint MoX

Cloud services are evolving quickly and the lines between managed hosting, co-location, and cloud services are getting fuzzy, especially as marketers interject the word “Cloud” into just about anything to capitalize on the current cloud hype.

Nemertes defines three primary classes of cloud services:

1. Infrastructure as a Service (IaaS). IaaS is the provisioning of storage, network, and processing as a platform for customers to load, run, and manage OS and application stacks. IaaS is essentially virtual co-location except the provider owns the hardware and software up to the operating system. One of the earliest players is Amazon Web Services (AWS) with its Elastic Compute Cloud (EC2) and Simple Storage Service (S3). There are hundreds of service providers offering IaaS.

2. Platform as a Service (PaaS). PaaS is the delivery of a complete middleware, development and run-time environment for full application development. The service provider provisions PaaS on IaaS. Google App Engine and are examples of PaaS.

3. Software as a Service (SaaS). SaaS is the most mature of the three cloud services. Functionally, SaaS can be a virtual version of managed hosting with the management responsibility shifting to the service provider. Examples include and Siebel OnDemand. Key characteristics of SaaS are:

a. Per-seat usage-based pricing

b. Web delivery

c. Management of the application, user provisioning, upgrades, etc., is the responsibility of the services provider.

During the next three years, we will see significant expansion of IaaS and PaaS offerings as the underlying virtualization infrastructure matures and as traditional WAN carriers get into the cloud infrastructure market.

Currently, IaaS, SaaS, and PaaS are proprietary systems: Signing-up with Google for PaaS locks you in to Google. There are movements afoot including Open Platform as a Service (OPaaS) and Open Virtualization Format (OVF) from the Distributed Management Task Force (DMTF) to facilitate moving applications, virtual machines and storage from one provider to another.

Cloud vs. Co-Lo

Co-location providers come in two basic varieties: Carrier-based and carrier-neutral. A carrier-based provider is a communications service provider that also offers co-location services. A carrier-neutral provider is similar in function – getting the processing as close to the network as possible – but the communications service provider is different from the outsourcing provider. Carrier-neutral providers such as Equinix, TelX, and 365 Main co-terminate with up to hundreds of telecom service providers. The end-result is the same, moving processing as close to the end-user networks.

Co-location facilities optimize on availability, cost, and communications. The highest level of availability is a Tier-IV data center with multiple, independent, physically isolated systems. This means each system has its own redundant capacity components and diverse distribution paths. There is no single point of failure and any component (transfer switch, PDU, HVAC, generator) may fail without any affect on operations. This is a very expensive proposition, but with significant economies of scale. For example, a 15,000 square-foot (175 watts/square foot) data center requires 2.63 MW of power generation. The smallest Caterpillar generator generates 2.76 – 4.19 MW of power supporting a 15,771 to 23,943 square-foot data center; 60% more floor space. The same economies of scale apply to power distribution, backup and facilities requirements such as building security.

Like co-location, not all managed hosting is alike. Managed hosting providers have an underlying data center (or co-location facility) that conforms to one of the levels of availability and redundancy discussed above. Managed hosting providers also must guarantee the availability, reliability and quality of their hosting services.

The bottom line, converged solutions managers looking to take advantage of the “cloud” need to familiarize themselves with the various flavors of cloud solutions – IaaS, PaaS, and SaaS, as well as delivery models including co-location and managed hosting.

Copyright © 2011 IDG Communications, Inc.

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