Cloud Computing needs Cloud Storage

I recently spoke on a panel at the Cloud User 2009, held in San Diego, on the subject of "Navigating the Cloud Vendor Community to Achieve Sped of Migration and Ease of Use". We were originally scheduled for an hour of discussion, but due to a subsequent presenter not showing up, and great interest from the audience, we went a half an hour over schedule.

My presentation was focused on the need for all IT infrastructure to be capable of supporting cloud computing. Often, people organizations focus on one or two aspects of cloud computing (often virtualization and elastic computing), while not always taking into account the impact, requirements and dependencies on other areas of IT.

I started out by reviewing a mapping of the U.S. Government's Service Component Reference Model into the Cloud model. This diagram provides a good example of all the different areas that IT and business organizations need to consider when embarking on a cloud project. This diagram is quite effective to discuss interdependencies between different technologies and IT areas of expertise.

Cloud Storage as a co-requisite for Cloud Computing

After introducing the concept of cloud as a holistic IT practice, I spent some time focusing on the specific dependencies that cloud computing has on storage, and how cloud computing drives the need for cloud storage.

	Cloud Computing Drivers	Emerging Storage Needs
Self-contained "Packages"	Virtual Appliances, vApps	VM Image Mgnt & Object Stores
Location Independence	Hybrid Clouds, vMotion	Distributed & Multi-site Storage
Loosely Coupled	Dynamic Provisioning	Simpler & Less Fragile Interfaces
Scale-Free	Elastic Scaling, Billing on Usage	Tiering & Dynamic Placement
Shared	Co-Hosting	Multi-Tenancy & Storage Security

The above table maps many of the business advantages and approaches for cloud computing to new requirements for storage that emerge as a result. Let's review these in detail:

Self-contained Packages

As the environment and resources for a given application or computing problem is packaged up and managed at the VM and application level, new requirements are created around managing these images and associating data with VM sessions and applications to allow them to migrate together, be snapshotted together, managed together, etc.

Thus, when you move to cloud computing, you need a new way to package up the data along with the applications, and ensure that they are self-contained.

Location Independence

These packages and data then must be able to migrate, both within the enterprise (such in DR and Business Continuity applications), and between organizations, when utilizing hybrid and public clouds. Once the stored data is packaged, this becomes easier, but often data movement must be more granular, as some data may need to remain within the organization, or may need to be spread across multiple clouds.

Thus, when you move to cloud computing, you need to make your data accessible from multiple locations, and ensure that it is consistent, complete and correct.

Loosely Coupled

One of the benefits of cloud computing is loose coupling between systems. This allows simple reconfiguration, enables the mixing of applications and infrastructure to quickly create new applications and update existing applications. The resulting collections of services are dynamically provisioned, and often do not involve people. In order to accomplish this, you need to ensure that all of the parts fit together, and can be controlled to dynamically assemble systems programatically.

Thus, when you move to cloud computing, you need to have simpler and less fragile interfaces to allow storage to be dynamically connected up to storage, as needed, when needed.

Scale-Free

In order to quickly scale up and down cloud computing environments, one needs to be able to deploy applications and storage in a scale-free manner. Being able to dynamically create a thousand-node compute cluster is not of much use if there is not also storage infrastructure that can scale to support this cluster.

Thus, when you move to cloud computing, you need to ensure that your storage is also capable of scaling elastically, and is capable of tiering data so that it is available at the right cost and performance. Often, one of the first problems one runs into when deploying an elastic computing infrastructure is mismatches between computing and storage, and the cost of keeping all the data resulting from the cloud computing activities.

This is important: Cloud computing results in an explosion of data, and this data has to be tiered in order to stay economical.

Shared

While less of an issue with private clouds, multi-tenancy and support for multiple users on shared infrastructure is critical for leveraging many of the economic advantages resulting from resource pooling. However, this sharing brings requirements for partitioning and security to prevent unauthorized disclosure of data. When storage is shared, there must be strong assurances that information will continue to be protected.

Thus, when you move to cloud computing, especially in public and hybrid clouds, the placement and security of stored information must be carefully assessed to ensure that additional risks are not introduced.