The Design of the Cloud Data Management Interface
Designed to enable interoperable cloud storage and data management, the CDMI specification is aggressively addressing a total cloud storage solution. This solution helps users avoid the chaos of proprietary advances and partial-solution APIs that would erode the integrity of the cloud model.
Easy to implement, CDMI integrates and is interoperable with various types of client applications and is designed to be compatible with current public cloud storage offerings. CDMI offers standard approaches to data portability, compliance, and security. It also offers the ability to connect one cloud provider to another, enabling compatibility among cloud vendors.
Providing both a data path to the cloud service and a management path for the cloud data, CDMI is the functional interface that applications use to create, retrieve, update, and delete data elements in the cloud. As part of this interface, the client will be able to discover the capabilities of the cloud storage offering and use this interface to manage containers and the data that is placed in them. The semantics of CDMI are straightforward; simple containers and data objects are tagged with metadata—some of which are metadata that describe the data requirements of the object or container. The protocol for accessing the data and metadata is RESTful HTTP, first outlined by Roy Fielding.
How CDMI Will Roll Out
Since CDMI can be used as both a data path and a management path, there are several ways to deploy an implementation of CDMI for a private, public, or hybrid cloud. First of all, CDMI can be deployed side by side with existing proprietary interfaces. This deployment allows existing applications to move over to the standard interface when they want to take advantage of the features.
The side-by-side deployment allows the same data to be accessed via either interface, and no movement of data is required. As the cloud provider adds additional data services and capabilities to their service, the application can use the CDMI interface to ensure that the existing data requirements are being met using those new services. If the cloud provider implements the CDMI accounting, users can use that function to administer the security and to programmatically access their bill.
CDMI has many capabilities and not all will be implemented by every cloud offering. CDMI has capability resources that let a client application programmatically find out which capabilities are actually implemented before trying to use them. This feature also allows new cloud offerings to use CDMI as the initial interface for their service, expanding the implementation of CDMI as the offering increases capabilities. CDMI is also extensible to accommodate services and features that are not yet standardised, which means that those functions will not require separate, proprietary interfaces.
There are many advantages to using public, private, and hybrid clouds as part of an organization’s long-term storage strategy. In private/hybrid models, internal IT departments have more control of their data (vs. public clouds) without needing to actively manage it, resulting in significantly lower costs than traditional storage. Public clouds offer the availability of storage capacity on a pay-as-you-go basis, combined with scalability and ease of use and can offer much needed cost savings.
CDMI, by enabling interoperable cloud storage and data management, provides a new paradigm of managing all cloud environments, while maintaining the simplicity that makes the cloud approach attractive. With its total cloud storage solution, CDMI is helping users avoid concerns around proprietary cloud advances and partial-solution APIs, while helping to maintain the integrity of the cloud model.
This article is based on a series of SNIA tutorials on cloud storage technologies. To view all of the tutorials on Data Protection and Management, visit the SNIA Europe website.
It was written by Alex McDonald, SNIA Europe UK Country committee member. He works for NetApp.
About the SNIA
The Storage Networking Industry Association (SNIA) is a not-for-profit global organisation, made up of some 400 member companies spanning virtually the entire storage industry. SNIA's mission is to lead the storage industry worldwide in developing and promoting standards, technologies, and educational services to empower organisations in the management of information. To this end, the SNIA is uniquely committed to delivering standards, education, and services that will propel open storage networking solutions into the broader market.
About SNIA Europe
The Storage Networking Industry Association (SNIA) Europe is dedicated to educating the market on the evolution and application of storage infrastructure solutions for the data centre by providing thought leadership and industry education focussed on storage technologies and business value. For more information visit: www.snia-europe.org.