Pure has taken AFA storage to the next level by designing their own, DirectFlash NVMe storage modules and controllers and using them in their new FlashArray//X storage array.
DirectFlash & FlashArray//X
Soon all AFAs will change over to use NVMe storage, but with DirectFlash, Pure is already there. They designed and implemented their own NVMe flash modules, connected them through their current midplane to new FlashArray//X controllers, and shifted flash management to be performed globally within their Purity software. By using DirectFlash, Pure can provide higher and more consistent IO performance with denser storage and eliminate much of the overhead of normal SSD, or NVMe SSD drives.
Unlike flash systems that use standard SSDs and even differentiated from the flash systems that design their own flash storage, Pure’s DirectFlash allows FlashArray//X to supply better, more optimized flash management. Yet Pure does so using commodity silicon and NAND and as such, can continue to directly benefit from Moore’s law. Essentially, this means that Pure’s FlashArray//X manages and operates at the physical NAND level, which offers customers:
- Adaptive IO control which offers flash level quality of service and global flash level IO queue scheduling that helps to understand what’s going on at the flash level, providing more consistent/deterministic IO response times.
- Smart endurance which uses global flash allocation maps, wear leveling and garbage collection that provides a storage system tuned, unified pool of flash storage for data writes to supply higher overall NAND endurance, better write IO performance and less write amplification.
- Predictive resiliency which provides system wide NAND block level telemetry, bad block management and data encryption that allows FlashArray//X to better understand system wide resiliency and provide data security.
DirectFlash modules plug into the FlashArray midplane which is already pre-wired for NVMe storage. The current FlashArray//M already uses dual-ported, hot pluggable NV-RAM modules over NVMe protocols.
Behind a DirectFlash module are multiple PCIe lanes for parallel IO and on the DirectFlash module are a NAND control chip for low level control logic and the MLC or TLC flash storage. Pure currently offers 2.2TB, 9.1TB (now – in Directed Availability) and 18.3TB raw capacity (at General Availability) DirectFlash modules with a PCIe Gen3x2 lanes into each module. With 18.3TB DirectFlash modules, a fully populated FlashArray//X offers 366TB of raw flash or at Pure’s average 5:1 data reduction, this equates to a little over 1PB of effective usable capacity in 3U.
To upgrade FlashArray//M systems to FlashArray//X, add a SAS expansion cabinet, move the current SAS flash modules up to the expansion cabinet, let Purity recognize the new flash module placement, swap one FlashArray//M controller with a new FlashArray//X controller and then the other. You are then ready to add DirectFlash storage modules to the empty FlashArray//X chassis. Once the DirectFlash storage is added to the system, all new writes will go to DirectFlash storage. This entire upgrade process can be performed non-disruptively.
In an Oracle environment, a new Pure FlashArray//X offers 30% more throughput than their previous generation systems. DirectFlash also delivers up to 50% lower latency, twice the bandwidth, and four times the performance density. Peak FlashArray//X performance can be achieved with only ten DirectFlash modules. This high-performance density also means FlashArray//X can support top-of-rack deployments. Overall, the FlashArray//X allows up to twenty DirectFlash modules with direct parallel connections between all DirectFlash modules and the two FlashArray//X controllers.
Other, new Tier 0 NVMe shared storage arrays, using standard off the shelf NVMe SSDs, are starting to show up. These systems have high performance with extremely low latencies but lack fundamental data services. Pure’s approach, using off the shelf NAND chips in a Pure engineered NVMe DirectFlash module with all of Purity’s advanced management capabilities allows them to be first in the market with a fully NVMe based storage system AND all the advanced data services required by the enterprise market. Pure intends to offer the FlashArray//X at a modest price premium relative to the //M, to make NVMe solutions available to a broad range of customer environments.
However, the competition will not stand idle. If anything, recent market history has taught them that allowing anyone a head start in technology transition leads to lost market share. This time, it will not take quite as long before the rest of the industry adopts NVMe storage. The critical question is not when they will adopt NVMe but at what performance, with what data services, at what price point and with how much disruption of current data access. Pure’s DirectFlash and FlashArray//X will be hard to match without significant time and effort.
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Silverton Consulting, Inc., is a U.S.-based Storage, Strategy & Systems consulting firm offering products and services to the data storage community