In the last few years, flash storage technology has made significant strides towards becoming a widely accessible mainstream option for IT administrators from companies of all sizes.

Once considered an expensive niche option limited to elite-performance data centres, the price of flash-based solid-state drives (SSDs) has dropped noticeably as the technology matures, allowing a broader range of businesses to take advantage of its ultra-high-speed performance.

However, flash arrays remain costlier than traditional hard disk drives (HDDs), which is why many organisations are adopting a hybrid approach that combines HDD and flash storage, rather than moving straight to an all-flash setup.

As such, IT administrators who are considering upgrading their data centres to flash storage now have a choice of whether to opt for an all-flash array, or an adaptive model that pairs SSDs with a bank of traditional HDDs. Each approach has its own advantages, and the right choice is likely to depend on the specific needs and priorities of the user in question.

With this in mind, it’s worth exploring the capabilities and qualities of each solution before coming to a decision about which is more appropriate for your organisation.

The key differences between all flash and adaptive flash

As the respective names suggest, the core difference between all-flash and adaptive flash solutions lies in the degree to which they rely on SSDs comprised of flash memory, rather than the older spinning hard disk technology that’s been an industry standard for so many years.

Flash storage is known for enabling significant improvements in data processing operation speeds, allowing multi-terabyte databases to be stored "in-memory", with a read/write speed that is four times greater than HDD.

However, the relative newness of the tech means that the overall cost remains higher on a per-gigabyte basis, meaning it can be much harder to get hold of the kind of multi-terabyte storage capacities that businesses require when relying solely on flash.

Adaptive flash arrays offer a lower-cost alternative by foregoing the all-flash model in favour of a setup that utilises SSDs and HDDs within the same unit, allowing frequently-accessed hot data to be stored on the flash component, while more static information is placed on the HDDs.

Naturally, these arrays cannot quite match all-flash in terms of raw performance, but they are nevertheless extremely capable systems that can greatly outstrip a purely HDD-based approach, often much more affordably than would be possible with a pure SSD setup.

When are all-flash arrays the best option?

The cutting-edge technology at the heart of all-flash arrays mean they are able to deliver a number of key benefits compared to adaptive flash, or any other form of storage that still relies on HDDs:

• Capable of performing faster input/output (I/O) operations than any other storage format
• Flash is more dense than HDD storage, meaning all-flash arrays can hold more data per rack unit than is possible with HDDs
• Typically smaller, taking up less space on the storage rack
• Lack of mechanical components means they are less prone to failure, use less power and have a reduced cooling requirement
• Offer the ability to scale up performance and capacity independently and non-disruptively, managing the entire array as a unified block

Even though the upfront purchase price of all-flash arrays are relatively high, many of their advantages serve to bring down their overall lifetime cost of ownership to a greater degree than many businesses realise, meaning they may even offer cost-effectiveness benefits over time.

The specific qualities of all-flash arrays mean they are best suited to organisations with particular needs:

• Businesses housing large quantities of hot data that needs to be accessed frequently, with sub-millisecond latency and near-constant availability
• Organisations with a focus on data efficiency, who are able to performance-optimise their storage and consolidate their information into a limited number of high-performance arrays
• Companies with the means to spend bigger upfront on a more advanced and immediately disruptive solution that delivers its cost-effectiveness gains over time

When are adaptive flash arrays the best option?

The combination of storage methods used in adaptive flash arrays means they are able to blend the characteristics - and most of the key advantages - of both technologies into a single solution. These include:

• Significant flash-enabled speed and data accessibility benefits compared to a pure HDD solution, without the same short-term costs of an all-flash system
• Retaining the predictability and familiarity of an HDD-based storage solution while adding flash capabilities incrementally - an important priority for companies looking to make a slow transition from a legacy setup
• Access to generally larger storage volumes at a lower cost, reducing the need for data reduction, compression and deduplication
• Flexibility in terms of the amount of SSDs and HDDs used in a particular array - configurations can be tailored and tweaked over time, offering the option to gradually scale the number of SSDs used over time
• The ability to segment data between flash and non-flash databanks, depending on accessibility needs and priority status

Although adaptive flash arrays share some of the traditional limitations of HDD technology in terms of speed and physical design, their flash components offer game-changing performance improvements that are significant enough that many organisations do not require a subsequent upgrade to an all-flash array.

Adaptive flash arrays are most suitable for organisations looking to attain the best-optimised cost per gigabyte, including:

• Those whose budgets cannot accommodate an all-flash solution, but that nevertheless require a significant performance upgrade in the short term
• Companies with unpredictable workload characteristics, and a balance of hot and cold data that needs to be stored and processed flexibly
• Businesses whose services do not require instant high-speed availability of data at all times, and are able to trade variable latency for cost-saving practical benefits elsewhere
• Organisations whose storage needs are driven by large banks of rich media and static images, which are incompatible with the compression and deduplication techniques upon which all-flash arrays rely
• Firms that are keen to make a more gradual transition to SSDs, scaling up their investment in the newer flash technology over time

Where can I find out more?

The beauty of the choice between all-flash and adaptive flash arrays is that either option can deliver transformative benefits for organisations in the right context. This is why it’s best to learn as much as you can about the specific pros and cons of each option, before deciding which approach it most likely to suit the needs of your business.

Checkmark IT has put together a comprehensive guide to HPE Nimble Storage, one of the leading brands in all-flash and adaptive flash technology, which provides more information about the characteristics of each approach and some of the most advanced products HPE offers in both categories.

Additionally, Checkmark IT is well-positioned to help businesses design, supply and implement the most effective storage solutions for their specific needs. We are accredited HPE partners, but maintain a vendor-agnostic approach to solution design and implementation, with a strong focus on what works best for your organisation.