Radian Memory Systems Releases Symphonic™ Cooperative Flash Zones

Calabasas, CA /PRNewswire/ - Radian Memory Systems®, Inc. brings Flash zones to data center storage for the first time with the release of its Symphonic™ Cooperative Zones technology available on its RMS-350 U.2 SSD and RMS-325 edge card SSD. Based upon Radian's award winning technology, Symphonic Cooperative Zoned SSDs include several key industry milestones, including being the first SSDs to provide Flash zones, zone tiering, and an 'All Firmware' SDF implementation.

• Cooperative ZonesSymphonic Cooperative Zones are contiguous logical blocks of 'Idealized Flash' that come from the same physically isolated regions of memory and can be associated with namespaces. Configurable in capacity, Flash management of these zones is performed by the SSD under cooperative host control.
• Zone tieringSSDs can be factory configured with different zones supporting different memory types (e.g., SLC, TLC, and NV-RAM today, and SCM or QLC in the future).
• 'All-Firmware' SDF SSDSymphonic 'Idealized Flash' and 'Configurable Addressing' are completely in SSD firmware. No host libraries are required for log structured hosts, making the SSD less OS dependent and optimal for SPDK applications.

Radian delivered first evaluation units of its Cooperative Zoned SSDs to OEM customers over a year ago, in January 2018. Available on Radian's NVMe 2.5" U.2 RMS-350 SSD and RMS-325 HHHL edge card SSD, Symphonic Cooperative Zones bring configurable and deterministic Flash zones to storage applications throughout the data center. For use in storage arrays, hyperconverged appliances, and Software-Defined Storage frameworks, Cooperative Zones can minimize write amplification while providing maximum parallelization and I/O isolation. The result is dramatically better tail latencies, bandwidth, overprovisioning and endurance than found with conventional FTL based SSDs.

Radian publicly introduced the industry to the concept of Flash zones in September 2015, at the SNIA annual Storage Developer's Conference (SDC) held in Santa Clara, Ca. Providing a talk titled "Integrating Cooperative Flash Management with SMR Technology for Optimized Tiering in Hybrid Systems," Radian illustrated how its Cooperative Flash Management (CFM) technology could enable Flash zones, and use SMR commands and tiering to more deterministically and efficiently perform SSD Flash management.

Problem Statement
Conventional SSDs with embedded Flash-Translation-Layers (FTLs) perform Flash management processes (garbage collection, wear leveling, and NAND maintenance) asynchronously, when the SSD autonomously deems necessary. This black box approach leads to unpredictable performance and latency spikes that can only be mitigated with overprovisioning. More recent workarounds propose achieving determinism by turning off I/O access to large portions of the SSD for periods of time. But this approach is impractical for most systems without employing even more overprovisioning.

Cooperative Zones
Symphonic Cooperative Zoned SSDs present the host with idealized, configurable Flash zones that can be associated with namespaces. Cooperative Zones are comprised of NAND Erase Units (blocks) that are subsets of the same physically isolated region of memory and are configurable in size. Zones are accessible via conventional Logical Block Addressing (LBA) through the NVMe command set. Certain SMR zone commands, such as Zone Report and Zone Reset, are supported as part of extensions to the conventional NVMe command set.

Accessing a Symphonic Cooperative Zoned SSD follows the same host/device model as earlier Symphonic SSDs. This enables the host to control data placement while the SSD abstracts lower level media management, including geometry and vendor-specific NAND attributes ('Idealized Flash'). Flash management processes such as garbage collection, wear leveling, and NAND maintenance are executed by the device, under cooperative host control, and hence performed deterministically.

Tiered Zones
Symphonic Cooperative Zones offer a simple, logical model to access different memory types as different zones on the same SSD, from NV-RAM to Storage Class Memory to NAND Flash, and different classes of NAND Flash. Variations of SLC NAND can provide very low latency and high endurance, while TLC NAND provides better capacity and cost efficiencies. The architecture can support factory configured zones designated as SLC, or TLC, or NV-RAM zones today, and other memory types such as QLC, SCM, and specialized ultra low latency SLC variations in the future. Combined with Radian's Delegated-Copy Move technology, this enables hosts to readily apply tiering between zones based upon different memory technologies to optimize efficiency trade-offs for cost, performance, capacity and endurance.

First 'All Firmware' SDF SSD
Until now, Software-Defined Flash (SDF) SSDs have either not offered "Idealized Flash" or "Configurable Addressing," or, in the case of Radian's SDF SSDs, required proprietary host resident libraries to provide this functionality. Symphonic Cooperative Zoned SSDs are the first SDF SSDs to provide this functionality completely in device firmware, without requiring any host libraries. This obviates the issues of having to integrate proprietary vendor libraries into host system software and minimizes OS compatibility requirements. The 'All Firmware' implementation is especially advantageous in SPDK environments which do not require NVMe device drivers or use of the kernel block layer, as existing targets can access the Cooperative Zoned SSDs directly without transitioning through intermediary libraries.

ZBD to NVMe Bridge
Radian offers an optional host library to customers already using the zone block device (ZBD) interface. Providing a protocol translation from the zone block device interface to NVMe, this bridge enables system software to access the Symphonic Cooperative Zoned SSD as a NVMe block device using a subset of the SMR zone block device commands.

Symphonic Cooperative Flash Zone configurations of the Radian RMS-350 U.2 SSD and RMS-325 HHHL SSD are available now to cloud providers and system OEMs.

About Radian Memory Systems
Radian Memory Systems, Inc. develops technology and products that target system OEMs, cloud providers, and licensing to device manufacturers. Founded in 2010, thousands of the company's NVMe storage devices have been successfully deployed in data center applications by some of the industry's largest OEMs. To learn more about Radian Memory Systems contact the company at (U.S.) 818 222 4080, info@radianmemory.com, or visit www.radianmemory.com.

All Registered symbols and Trade Marks are the property of their respective owners.
Copyright Radian Memory Systems, Inc., February 2019