Five (and Soon Six) Classifications of All-Flash Arrays

This analysis was published on February 1, 2018 by Jerome M. Wendt, lead analyst, DCIG LLC.

Five (and Noon Six) Classifications of All-Flash Arrays

The all-flash array (AFA) market has settled down considerably in the last few years. While there are more AFAs (90+ models) and vendors (20+) than ever before, the ways in which these models can be grouped and classified has also become easier.

As DCIG looks forward to releasing a series of buyer’s guides covering AFAs in the coming months, it can break these AFAs into five (and soon to be six) general classifications based upon their respective architectures and use cases.

When flash first started to find its way into storage arrays around 2010, these AFAs generally found themselves in two general groupings. On one side, you had existing storage arrays built to hold and manage HDDs being re-purposed and filled with SSDs. On the other side, you had emerging and new start-ups that were bringing to market AFAs purpose built to manage and optimize flash.

Unfortunately, neither one really addressed the concerns that enterprises had. Existing storage arrays addressed data management, stability, and reliability concerns, but did not really deliver on the potential of flash’s performance characteristics. New AFAs purpose-built for flash largely delivered on flash’s potential for performance, but still left question marks in their minds in terms of their stability, reliability, and levels of support.

Those concerns on both ends of the spectrum have largely been put to rest by the current generation of AFAs. While differences between their respective data management, performance, reliability, scalability, and stability on each platform yet remain, the gaps between them are not nearly as wide as they once were. It is as these gaps have closed that five specific AFA architectures have emerged that make certain models better positioned to handle certain use cases than others. These five include:

• 1 Elastic AFAs. This classification of AFAs is best represented by the generation of AFAs that were purpose-built for flash. This includes models such as those from Dell EMC XtremIO, Kaminario, Nimbus Data, and Pure Storage though DCIG would also include models from HPE Nimble and Dell EMC Isilon in this group. The defining characteristic of this group would be their ability to do scale-out, which encompasses the ‘set-it-and-forget-it’ nature of these AFA models.
• 2 Enterprise AFAs. These arrays are best represented by Dell EMC VMAX, HPE 3PAR, Huawei OceanStor, NetApp AFF and Western Digital Tegile models. These arrays offer both scale-out and scale-up configurations and are well suited to provide the high levels of performance (1+ million IO/s), do consolidation, and handle the mixed workloads found in enterprise environments.
• 3 General purpose AFAs. This classification of AFAs is best represented by products such as Dell EMC Unity, FUJITSU Storage ETERNUS AF Series, Hitachi Vantara VSP F series, Nexsan Unity, and the NEC Storage M Series. These are the dual controller storage arrays that have had their controllers updated to better manage and optimize the performance of flash while bringing forward their more mature data management capabilities.
• 4 High performance AFAs. This is an emerging class of AFAs which are only starting to come to market now from vendors such as E8 Storage and, later this year, from Kaminario. This class of all-flash arrays will redefine ‘high performance’ by offering 10+ million IO/s using NVMe-oF on their front-end interfaces to hosts. While the practicality of implementing these AFA solutions is limited in the near term, these arrays provide an early glimpse of what is coming in the not-too-distant future.
• 5 Utility AFAs. This final grouping of AFAs includes products such as the HPE MSA series, the IBM FlashSystem 900, the NetApp E-series, and SanDisk Infiniflash. These are for organizations who only intend to connect a relatively few number of applications to the AFA, need high levels of performance and reliability, and not a whole lot more. Due to the reduced number of data management features on these arrays and their purpose-built nature, they often come at a very attractive price point on a raw per gigabyte basis when compared with the other AFAs mentioned here.

This maturing of the AFA market, however, comes with a caveat. It appears another round of maturation will again occur in the next 5-10 years that will create yet a sixth and perhaps final class of AFAs: Composable AFAs. This final classification may actually serve to be end game for all five of these current AFA classifications as software-defined storage takes hold in enterprises and the need for AFAs to manage and deliver both data management and performance decreases. While that day does not appear to be imminent, in light of how quickly enterprises are adopting the cloud architectures and software-defined storage, the adoption and spread of composable AFAs may occur more quickly that many suspect.