Flash Memory Summit Briefing Note: Radian Eliminates Flash Translation Layer for Improved Performance, Endurance, and Cost
The first generation of flash storage devices addressed backward compatibility by treating the devices as if they were hard drives through the use of the flash translation layer (FTL). The problem is, of course, that flash devices are not hard disk devices, and the overhead that the FTL adds to achieve compatibility introduces inconsistent latency. Radian Memory believes that the industry is ready to move on from the FTL era and to a software solution built for flash storage that lowers latency, decreases costs and increases durability.
The FTL Barrier to Optimal Flash
Most storage and file systems today have a broad range of data services. These systems can offer RAID, snapshots, thin provisioning, replication, cloning, and automated data tiering. They also try to control how data is written to the storage media they support. Today these write patterns are optimized for hard disk drives, but storage system and storage software vendors clearly have the capability to optimize their writes patterns for flash. The problem is that the FTL stands between the storage system and the flash media. In other words, the storage system does all this optimization and then the FTL takes over control of how the data is written.
Lack of visibility into how the storage system intends data to be written forces the FTL to operate in the blind. This lack of clarity leads to latency spikes as the FTL organizes writes and performs garbage collection. To ease the impact of these spikes vendors have resorted to over-provisioning that increases the cost per unit of a flash solution.
Software Defining Flash
The Radian Memory solution to FTL is to provide a native software layer that manages flash directly from within the storage system’s software, the operating system or the file system. If any of these storage providers understand space management or are virtualizing storage at a block, file or object level, they should be able to integrate Radian’s technology in short order. A storage system or software that can control how data is written to the flash media should allow for more consistent write performance, reduced capacity dedicated to over-provisioning and decreased write amplification, which will increase flash durability.
The capabilities of today’s storage systems and software are impressive. In most cases, these systems are already in full control over how data is written and organized within their infrastructures. It makes sense that they should want to leverage their intellectual capabilities and control flash media directly. Vendors that take advantage of a solution like Radian’s should be able to provide a more consistently performing system, which has a better price per GB and lasts longer. In short Radian allows storage system and software vendors to innovate.
so the flash storage is slow compare to spindle ones