Author: mac

Lots of people are wondering what CDMI offers, but don’t have time to read the actual specification to understand all it’s features in depth.

Here is a short (20 min) overview of the CDMI features and architecture that should get you started.

You can also download the overview presentation for viewing offline.

The SNIA has released a final working draft of the Cloud Data Management Interface (CDMI) version 1.0. The folks that have put this specification together in record time include:

Company – Individual
Bycast Inc. – David Slik
Cisco Systems – Mike Siefer
Hitachi Data Systems – Eric Hibbard
Iron Mountain – Chris Schwarzer
NetApp Inc. – Alan Yoder
NetApp Inc. – Lakshmi N. Bairavasundaram
Olocity – Scott Baker
Oracle – Mark Carlson
QLogic – Hue Nguyen
Individual – Rich Ramos

Thanks as well for the comments from lots of folks outside of the SNIA. These have all been incorporated into this latest public review draft.

The specification is now in front of the SNIA membership for a vote to become a SNIA Architecture industry standard. It will also become both a National (ANSI) and International (ISO) standard down the road.

I have heard lots of FUD around standardization of cloud interfaces, including the notion that standards take “too long” and that they cannot evolve quickly enough to accommodate the rapid evolution of this new industry. The SNIA Cloud Storage TWG that created this specification was formed last April and has produced a robust 1.0 version of a cloud standard in less than a year – record time for a standards body.

The CDMI standard is extensible by vendors to cover the complete functionality of their cloud and can also be “shrink to fit” for clouds that don’t have all the bells and whistles of the full specification. These extensions are expected to be candidates for future version of the specification as multiple vendors implement them.

Storage and Cloud vendors who have putting off implementing CDMI until 1.0 was available, now no longer have an excuse! Customers of public and private clouds can now start asking their vendors to show adoption of the standard in their roadmaps. Tools and common API libraries can now proceed to add support for a standard cloud storage interface.

To get the Draft 1.0 CDMI specification, go here:

http://snia.org/cloud

The SNIA announced that version 0.9 of the Cloud Data Management Interface (CDMI) is available for download.

This version incorporates comments received from the initial public review back in September, as well as some new features. One feature is the ability to access specific byte ranges of a data object. Another important feature is the ability to access specific metadata elements individually. These features will help reduce the bandwidth required to perform certain operations.

We have also incorporated feedback suggesting better conformance to HTTP and the principles of REST. The document is easier to read and better explains the concept behind the interface. One of those is the notion of tagging the containers and data objects with Data System Metadata. Table 14 in chapter 16 now goes into much more detail on the various metadata tags that are standardized:

By tagging a data object or container of data objects with this metadata, specific data requirements are expressed to the cloud. If the cloud provider can deploy data services to meet these requirements, they can charge more as a result, leading to cloud storage that is better than the typical “best effort” services offered today.

For each of these elements, there is a corresponding “billed” value that the cloud provider supplies indicating how well the data requirement has been met. The better the service provided, the more they can charge as a result. This metadata is preserved in the serialized data format that is also standardized by CDMI so that as you move data from one cloud to another (Public<->Public, or Private<->Public), the data requirements can be interpreted interoperably by the new cloud.

There are many other new features in this version of CDMI, including a new security writeup. Please download and review this version and provide feedback over the next month so we can have a robust version 1.0 early next year.

The SNIA has released early drafts of a couple of documents created in the new Cloud Storage TWG. The Cloud Storage Reference Model sets out a model of cloud storage elements that describes a logical view of their functions and capabilities using a descriptive taxonomy. The purpose of the model is to form a basis upon which industry efforts can be organized, needed standards identified and vendor products can be described by vendor independent terminology. In addition, the model is used to describe standard interfaces for cloud storage.

The SNIA will create a new interface called the Cloud Data Management Interface (CDMI) that will serve as both a functional interface to store data in a cloud, and as a management interface for the data that is stored there.

SNIA is soliciting feedback on the model and use cases in order to shape this interface work. If you would like to get involved, there is a Google Group you can join.

Update: original Sun Blog post: 6/9/09