block层数据完整性Data Integrity

The integrity metadata (or protection information in SCSI terminology) includes a checksum for each sector as well as an incrementing counter that ensures the individual sectors are written in the right order.
完整性元数据包括每个扇区的校验和及增加的用来确保每个扇区正确的写入顺序的计数。

The SCSI Data Integrity Field works by appending 8 bytes of protection information to each sector. The data + integrity metadata is stored in 520 byte sectors on disk. Data + IMD are interleaved when transferred between the controller and target. The T13 proposal is similar.
scsi的数据完整性字段，通过附加8字节的保护信息到每个扇区来工作。数据和完整性元数据被储存在磁盘上的520字节的扇区。在控制器和器件之间传输时，数据和完整性元数据被交叉读取。T13提案也类似。

Because it is highly inconvenient for operating systems to deal with 520 (and 4104) byte sectors, we approached several HBA vendors and encouraged them to allow separation of the data and integrity metadata scatter-gather lists.
由于对操作系统来说处理520（和4104）字节的扇区非常不方便，我们和几个HBA供应商接洽，鼓励他们允许数据和完整性元数据的scatter-gather 列表的分开操作。