SAN-based intelligence: the Holy Grail of storage management? - Storage Networking - storage area networks

Computer Technology Review, Dec, 2003 by Bill Terrell

Some NSS Platform implementations will provide integrated hardware and software running in a proprietary environment. While this type of implementation has the benefit of tight hardware and software integration (like fabric switches running fabric services software), the disadvantage is the inability to support a rich offering of storage services software from a variety of independent software vendors. You're pretty much stuck with the software roadmap from the vendor of this type of NSS Platform.

Another approach, albeit more difficult, is to make the NSS Platform an open platform running a commercial operating system, with storage services-specific APIs that allow ISVs to port various storage applications to the platform. It's also important that the level of abstraction provided by these APIs and the porting architecture be carefully designed to minimize the development and testing effort. If done right, applications can be ported and brought to market quickly at reasonable prices. The more difficult the porting job is, the more it limits the number and type of applications that can be brought to market, resulting in longer time-to-market with higher product costs.

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The open version of an NSS Platform isn't just a static point product limited by a single vendor's ability to bring out new features. Rather, the open NSS Platform becomes a dynamic network footprint on which rich applications can be added over time to continually upgrade the centralized storage management capability of the SAN. This is a pragmatic, solutions-oriented approach to incrementally and non-disruptively adding intelligence to the SAN without having to "rip and replace" existing fabric, and without getting locked in to another proprietary software environment.

The open NSS Platform model has great promise, but what storage administrators really need are solutions to problems, not more complex technology to digest. And since many already have host-based software, existing SAN fabrics, various array-based storage services, and procedures and practices to manage these today, adding SAN-based intelligence should be an incremental and complementary project with measurable benefits. Fortunately, the NSS Platform can provide a rich toolset to cost effectively solve problems today without "boiling the ocean."

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For example, if online backup of an application server is over-stretching its backup window, a network-based snapshot capability can solve the problem. By inserting an NSS Platform to re-host the application servers' storage volume, an instant snapshot capability can create a copy volume that can be backed up offline by a separate backup server. Instant snapshots and copies can also be used to do application testing against production data without disruption of production applications. And since the NSS Platform snapshot capability lives in the network above the storage systems, it's not necessary to provide free disk capacity from the same, homogeneous storage type as used for the primary volume. If the primary volume is provided on expensive, monolithic storage, the snapshot backing-store can use less expensive ATA-based storage for offline backup or application testing purposes.