SNIA standard should help in moving cloud data

The storage group's new CDMI standard preserves metadata about content stored in public and private clouds

The Storage Networking Industry Association (SNIA) has finished a standard that should make it easier for enterprises to move data among public and private storage clouds.

The CDMI (Cloud Data Management Interface) specification is designed to preserve metadata about the content that an enterprise stores in a cloud infrastructure. It sets standards for defining service levels for data stored in a cloud, such as how long it should be retained, how many copies should be kept, and whether those copies need to be distributed geographically, said Wayne Adams, chairman of the SNIA board of directors.

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Like the folders used to organize data on a PC hard drive, this metadata can be critical for continuing to use information after it's been moved from one place to another, Adams said. But there haven't been any common standards for structuring that metadata that all cloud systems can understand, he said.

Cloud storage collects data in an infrastructure that can be distributed over many locations and reached via a public or private network. Products and services in this area are proliferating, giving enterprises many options for where to store their data. But if a user wants to move on from one cloud service to another, or to shift data between public and private clouds, they may lose information that's critical for organizing and managing that data, Adams said. CDMI provides standard ways to define the metadata so it doesn't have to be rewritten every time. It also includes a common data exchange format for moving the primary data and metadata from cloud to cloud.

SNIA is set to announce CDMI on Monday at Storage Networking World (SNW) in Orlando, just about a year after beginning work on the problem at last year's SNW. The group expects to see some implementations of CDMI in service offerings in the second half of this year.

Among other things, the kinds of information that CDMI defines can be used for setting up billing arrangements for the use of storage capacity and other resources, according to Mark Carlson, chairman of the SNIA's Cloud Storage Technical Work Group. That's a critical part of enabling enterprises to bill their own departments for storage use, or at least account for it financially, Carlson said. The standard is designed to allow for a direct comparison between the cost of storage on a public and a private cloud.

Cloud product vendors and service providers can choose which elements of the standard they wish to implement, but they will need to disclose what parts they do support, Adams said. They could either make that disclosure public or reveal it only to potential customers that set up an account, he said.

Also on Monday, SNIA is announcing it has begun conformance testing of products under the SMI-S (Storage Management Initiative Specification) 1.4 standard.

SMI-S is a standard for managing many pieces of storage infrastructure, such as fabric switches and storage arrays. Version 1.4 adds components for managing thin provisioning, remote copy services, host RAID (Redundant Array of Independent Disk) controllers, virtual fabrics and partitioned fabric switches.

As it announced that testing had begun, SNIA also announced that EMC, Hewlett-Packard, Hitachi Data Systems, and Hitachi had passed the interoperability test suite for SMI-S 1.4. The group tracks vendors' conformance with different versions of the standard on its Web site. Only commercially available products may be tested.

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