>>>>> "Eric" == Moore, Eric <Eric.Moore@xxxxxxx> writes: Eric> Martin K. Petersen on Data Intergrity Feature, which is also Eric> called EEDP(End to End Data Protection), which he presented some Eric> ideas/suggestions of adding an API in linux for this. T10 DIF is interesting for a few things: - Ensuring that the data integrity is preserved when writing a buffer to disk - Ensuring that the write ends up on the right hardware sector These features make the most sense in terms of WRITE. Disks already have plenty of CRC on the data so if a READ fails on a regular drive we already know about it. We can, however, leverage DIF with my proposal to expose the protection data to host memory. This will allow us to verify the data integrity information before passing it to the filesystem or application. We can say "this is really the information the disk sent. It hasn't been mangled along the way". And by using the APP tag we can mark a sector as - say - metadata or data to ease putting the recovery puzzle back together. It would be great if the app tag was more than 16 bits. Ted mentioned that ideally he'd like to store the inode number in the app tag. But as it stands there isn't room. In any case this is all slightly orthogonal to Ric's original post about finding the right persistence heuristics in the error handling path... -- Martin K. Petersen Oracle Linux Engineering - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
