Features - Enterprise Data Insights:

SANs: BEWARE OF FAUX INTEROPERABILITY
By Mike Drapeau, President, The Drapeau Group

It has been over four years since Storage Area Network (SAN) topologies have been commercially available. By and large, the major data storage vendors have grown accustomed to installing monolithic or modular storage platforms without too much trouble. Progress in this fashion has come at a cost though, as end user customers have suffered from implementation teams who underestimated the preparation work necessary to correctly configure a SAN.

It didn't take long for customers to realize that one way to mitigate their risk was to create their own SAN laboratories. Many of the larger data centers have done this or have incorporated storage product testing into their existing laboratory facilitates. In this way they can focus only on the storage technologies and conditions unique to their environment.

For the majority of organizations, however, this approach is too costly, so some of them turn to SNIA's SMI-Lab for help. SNIA (Storage Networking Industry Association) has operated an interoperability lab for several years and it serves as a showcase for 60-plus vendors to demonstrate their products can work together. This effort is noble, but is limited by the amount of available floor space at SNIA, the number of SNIA staff, and the astounding rate at which new storage technologies are being introduced. Every time a new element in a storage configuration undergoes a physical upgrade, firmware revision or feature change, the whole set of components needs to be re-validated. This is a Herculean task.

Additionally, a serious drawback to many lab environments is that they reflect a "test to work" approach rather than the more difficult, but useful "test to break" methodology. Vendors are anxious to show how their products work normally; but they are less excited about what happens when their products are subjected to multiple failure conditions. That is where a real interoperability lab achieves its mettle.

Furthermore, this type of testing applies only to the hardware side of the equation -- what matters just as much these days is evaluating how storage software (so much of which is still tied to array chipsets) reacts to the various heterogeneous hardware scenarios. Testing that adds an additional element of complexity. The SMI-S standard is gradually being eased into the marketplace and it should alleviate some of this challenge for storage software interoperability, but it will be some time before widespread adoption of SMI-S begins to overcome this obstacle.

So where does one find this type of interoperability rigor and discipline? Frankly, the only organizations who can boast of this capability are the major storage vendors themselves. They are the only players in the game with the financial wherewithal and technical competency to create and maintain such facilities. So, with that in mind, how can a storage buyer compare one lab to the next?

The key is in the matrix.

When looking at buying a new storage platform, buyers should make the vendor's interoperability matrix one of the decision criteria. This matrix should identify not only what component combinations are being tested but also to what failure conditions the configuration is being tested. Buyers should ask each vendor to demonstrate:

• the extent of their physical testing facilities
• what staff they have dedicated to testing
• how they implement a "test to break" methodology
• the range of vendor product in the lab
• the degree to which all of this information is made available to customers.

Also, take a look at the fine print on the cover of the matrix. Does it say that all tested configurations are certified to work with the full support of the vendor's service staff? Or, does it say that they worked at one time and that the vendor will make best efforts to get it to work in your environment?

So, if you do all of these comparisons, what will they reveal?

By looking at these aspects of a vendor's interoperability commitment, you will be able to appreciate how much emphasis they put on resolving problems before they arrive gift-wrapped as a new product release. You will be able to see the true extent of their investment in heterogeneity, how much understanding they have of the interaction between storage hardware and storage software, and how willing they are to disclose that even homogenous SAN configurations require extensive interoperability testing.

In almost all cases, there is no need to build your own lab. Look behind the covers of a vendor's interoperability testing capability and you can determine whether they are putting the money behind their marketing statements.

Pay attention to the matrix.

About Mike Drapeau

Mike Drapeau is president of The Drapeau Group, an Atlanta-based firm that delivers on the promise of vendor-neutral data storage consulting. They do not sell any hardware or software -- only advice -- and have offerings that range from strategy development to platform architecture review to regulatory compliance assessments.