No one likes to rip and replace. But sooner or later, you need to buy new stuff to upgrade or augment existing your storage infrastructure -- and each time you need to go to school on your options as if you'd never seen a SAN before. That's how fast the technology changes.
Those who buy new storage products based solely on feature lists, quick tabletop demos, and cost comparisons take a huge gamble. Though it's impossible to anticipate every single gotcha, the trick to avoiding a disastrous choice is in knowing the right questions to ask -- and where to get the answers.
Ultimately, the most valuable sources of information are customers who've already implemented the technology in question. Here are some questions you can ask to quickly get to the heart of what you need to know.
It's all about the software
The basic building blocks that form the storage hardware you're likely to consider buying today have largely reached commodity status. There's very little variation in the actual disk or disk interface hardware used across the market -- one vendor's 6Gbps 15K SAS drive is going to be very similar if not identical to another's. It's also increasingly common to see controller hardware that's based around the same general-purpose Intel and AMD processors you'll find in servers rather than the highly customized processors common in previous storage generations.
The wide availability of fast disks and high-performance server hardware have made it possible for even the greenest storage startup to slap together a Linux or BSD-based storage array that will compete well with the big names in terms of raw disk performance. Essentially, just about anyone can toss together a bunch of off-the-shelf SLC SSDs, 15K SAS disks, and a multicore Intel mainboard, then field a storage array with serious performance potential.
The real differentiation between storage options available in the marketplace today is almost entirely derived from the software running on those storage processors. That's where you see the real game changers implemented, such as snapshots, thin provisioning, deduplication, and automated tiering. The quality and reliability of those software features are what separate the wheat from the chaff.
Unfortunately, it's nearly impossible to get an impression of that software without actually using it for a long time. While it's true you can learn a lot from a tabletop demo, you'll mostly come away with impressions of the user interface's assembly and ease-of-use -- not of what really happens when you tick the boxes and start making changes. These are usually the details you'll want to learn the most about as you chat with references.