嵌入式中flash存储设备日志冗余管理

Log Redundancy Management of Flash Storage Devices in Embedded Systems

智能设备的flash存储系统中,基于会话的日志型文件系统一般为并行系统,由此导致同一个目标区域的会话中包含大量冗余备份,并占据flash的日志存储空间,对此,提出一种简单的两阶段冗余备份日志信息失效算法。首先,在文件系统中增加2个链表,一个是有效备份链表,另一个是无效备份链表。然后在日志会话的检查点态与提交态对无效备份链表的数据作失效处理,从而实现不将无效备份提交至日志存储区域中,以此减少了flash的写操作与擦除操作。最终基于开发板进行对比试验,结果表明,本方案有效地降低了写操作与擦除操作的次数,提高了flash存储系统的整体性能。

In the flash storage system of smart device, the journal file systems which based on the transaction are parallel systems, leading to the situation that the transactions which have the same target area have a large amount of redundancy backup, and the journal storage area is less, a two phase redundancy backup journal information invalidation schema is proposed for that problem. Firstly, two lists are added into the file system, one is the valid backup list, the other one is the invalid backup list. Then the data in the invalid list is invalided in checkpoint state and commit state, and the invalid backups are not committed to the flash storage, at the same time, the count of write operation and the erase operations is reduced. Comparison experimental results based on the evaluation board show that the proposed schema reduces the count of the write operation and erases operation efficiently, and improves the performance of the flash.