基于日志翻译层的冗余闪存阵列研究

为了适应在苛刻嵌入式环境下对闪存存储提出的高可用性和高可靠性要求,人们难免想到借鉴RAID的思想设计类似的闪存的冗余存储方案.但是,闪存的物理特性、接入系统的方式等均与磁盘有着较大差异,这就决定了不能在闪存上直接应用RAID机制.为了能在闪存上使用RAID,提出了日志翻译层(journaling translation layer,JTL).JTL通过建立逻辑擦除块到物理擦除块的动态映射来处理闪存芯片特有的物理限制;它引入日志系统到映射管理中,有效减少了对芯片的磨损,延长了其寿命,并提高了系统的鲁棒性.把类似的RAID机制建立在JTL之上,从而实现了冗余闪存阵列.

Research on Redundant Array of Flash Memory Chips Based on the Journaling Translation Layer

To satisfy the requirements of high availability and reliability of flash memory storage under harsh embedded conditions,people may have the idea of designing RIAD-like redundant flash memory arrays.However,flash memory has its own particular physical limitations and the way it is connected to the system is very different from that of disks,which makes it impossible for US to apply the RAID scheme directly.To solve these problems,JTL(journaling translation layer)is proposed in this paper.JTL maps logical blocks to physical blocks of the flash chip to overcome the physical limitations.It introduces the journal system to its mapping management so as to relieve the wear to the chip thus extends its life span.RAID-like schemes can be built on top of JTL so that redundant flash memory arrays are implemented.