SMI-S: Order from chaos

Bringing application awareness to an entire SAN of heterogeneous storage will require standards that integrate with every part of the storage stack, much like the QoS standards in the world of communications networking. To that end, the Storage Networking Industry Association (SNIA) has developed SMI-S (Storage Management Initiative Specification), a vendor-neutral storage management API specification based on WBEM (Web-Based Enterprise Management) architecture.

The goal of SMI-S is to allow management solutions to discover, monitor, configure, and control storage devices and each other without having to write to the multitude of proprietary APIs. It works by dividing the SAN into “clients,” which are SAN management solutions, and “providers,” which are the SAN devices being managed. Providers include host bus adapters, switches, arrays, and — in the future — NAS and tape devices. Each provider can communicate with a client through its own agent or a client can communicate with an object manager, which aggregates several devices under one agent.

As standards go, SMI-S is progressing reasonably quickly. Version 1.02 is expected to be ratified this month and more than 100 provider products from 15 vendors — including EMC, Hitachi Data Systems, HP, Network Appliance, and Sun — have passed the SNIA’s SMI-S conformance testing regimen. AppIQ and CreekPath have also engineered their management platforms around the API.

At this stage, vendors have the option of writing a native SMI-S interface or using a proxy to translate their own proprietary one. Most vendors have chosen proxies for now, but the hope is that new products will go native, to reduce complexity and make it easier to take advantage of new SMI-S features. Today, SMI-S can be used to discover devices, create zones on a SAN, allocate storage, and perform other similar nuts-and-bolts functions, but SNIA isn’t stopping there.

“Version 1.1 will move up from describing individual devices to providing services that applications can use to perform operations such as security, fault management, policy management, and data moving,” says Ray Dunn, chairman of SNIA’s Storage Management Forum. “This will let programs talk directly to services instead of devices.”

According to Dunn, SNIA is also working on standards for data protection, content management, and ILM. “The goal is to get vendors to call things and define things the same way, to create ILM reference architectures, and to begin developing specifications around how ILM will work,” he says.

These ambitious goals, if achieved, will do a lot to further SAN application awareness. Though standards can take years to develop and vendors don’t always cooperate, things seem to be moving in the right direction for SMI-S.