The Storage Networking Industry Association (SNIA) has finalised a standard aimed at making it easier for organisations to move data among public and private storage clouds.
The CDMI (Cloud Data Management Interface) specification is designed to preserve metadata about content housed 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, says Wayne Adams, chairman of the SNIA board of directors.
Like the folders used to organise data on a PC hard drive, this metadata can be critical for continuing to use information after it has been moved from one place to another, Adams says. But there haven't been any common standards for structuring that metadata that all cloud systems can understand, he says.
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 organising and managing that data, Adams says. 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 announced CDMI last week at the Storage Networking World (SNW) conference in Orlando, Florida, approximately a year after beginning work on the problem at last year's SNW event. 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, says 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 says. 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 says. They could either make that disclosure public or reveal it only to potential customers that set up an account, he said.
Also at SNW, SNIA announced 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 Ltd had passed the interoperability test suite for SMI-S 1.4. The group tracks vendors' conformance with different versions of the standard on its website. Only commercially available products may be tested.