Any story about all-flash arrays must start with a disclaimer: Very few companies are diskless.

Gartner stated nine months ago that less than one percent of data centers were all-flash at that time, yet the research house is predicting the figure will skyrocket to 50% by 2020.

For now, despite the hype, flash arrays are a modest part of a balanced storage diet wherever you look. Spinning hard disks will be phased out, but most people aren’t as bullish about when.

SEE: All-flash arrays: The smart person’s guide (TechRepublic)

Infrastructure planners who want a head start may have many questions. We turned to another analyst, Enterprise Strategy Group’s Scott Sinclair, for some answers.

TechRepublic: What’s the right time for an enterprise to consider switching from HDD storage to flash?

Scott Sinclair: Yesterday. According to our research as well as the anecdotal conversations I have had with CIOs, the benefits delivered by flash storage are transformational. In fact, I have yet to meet anyone who has said that his or her flash deployment was a mistake.

For those few remaining data centers without flash, here is a good rule of thumb for transactional workloads. If your current storage infrastructure has no issues whatsoever in scale, performance, reliability, management, etc., then you are probably fine to wait until your existing infrastructure approaches its end-of-life before switching to flash storage.

TechRepublic: Speed and reliability are the biggest advantages of flash; are there underreported advantages?

Scott Sinclair: According to our research, almost half of flash users reported improvements to both operational expenses and TCO. In other words, adding flash storage helps make the infrastructure easier to manage.

TechRepublic: Cost is the biggest downside; are there underreported disadvantages?

Scott Sinclair: Not really, cost continues to be the top inhibitor of flash deployments. Even though nearly half of storage decision makers reported that flash helped improve total cost of ownership, historically there has been a premium acquisition price for flash storage relative to [hard-disk drives] in terms of cost per capacity. Thanks to a lower cost of components and more efficient software though, that cost premium is almost non-existent today when flash is compared to higher performing HDDs.

TechRepublic: In 2017, should you switch only when there’s a specific application, or is it wise to switch simply to stay ahead of the curve?

Scott Sinclair: Outside of secondary storage environments, such as backup or long-term archive, flash storage very likely will be an improvement over your HDD-based storage environment for both new and existing applications. I recommend starting with your most performance-critical applications and moving on from there.

TechRepublic: How do you decide whether to go hybrid or all-flash?

Scott Sinclair: Both hybrid and all-flash will provide significant benefits over an all-HDD based environment. All-flash is more expensive, but the performance benefits are more predictable. With flash costs coming down, I would make all-flash my default option, and then select hybrid in the cases where the budget or business priority of the workload can’t support all-­flash.

TechRepublic: If you choose hybrid, then how do you make your HDDs and flash play nicely together?

Scott Sinclair: There are a number of storage industry players that have already solved this problem. If you decide to go hybrid, my recommendation is to evaluate the performance and the manageability of the solution prior to acquisition.

TechRepublic: Is the industry starting to see any unconsidered long-term effects of flash, either pro/con?

Scott Sinclair: A couple things have come up. On the positive side, there has been a lot of talk lately about IT, or digital, transformation. This can mean a lot of things.

When I think about IT transformation though, it is more than simply buying the latest and greatest stuff. It is that the new infrastructure can so dramatically improve your operations while delivering such a surplus in data performance that businesses can free up resources to address other business transformative projects, such as entering new markets or meeting customer demands in new ways. In addition, the added performance opens up opportunities to layer on analytics to existing data to become a more efficient and successful business.

SEE: Ebook–Digital transformation: A CXO’s guide (free PDF) (TechRepublic)

Flash storage has played a key role in enabling many businesses to undergo this IT transformation. One possible con has been for larger flash deployments. Flash eliminates the storage as the performance bottleneck, which is good. While the overall system performs significantly faster, finding the new bottleneck, once an organization hits it can be a challenge, however. It might be in the network, in the storage controller, or somewhere else. This typically isn’t an issue for mid-sized and even large workloads, but some high-performance enterprises are now having to identify and adjust to these new bottlenecks.

TechRepublic: What other points should buyers consider?

Scott Sinclair: With all the benefits flash provides, I would make flash storage my default choice for new storage infrastructure for transactional workloads. Obviously, storage decision makers need to evaluate the other elements of a solution before deciding, such as manageability, scalability, resiliency, etc. But with so many systems offering flash as an option today, that is often a separate consideration.