>>>>> "Dave" == Dave Chinner <david@xxxxxxxxxxxxx> writes: Dave> 2TB chunks, IIRC - the lower 32 bits of the 48bit LBA was intended Dave> to be the relative offset into the region (RBA), with the upper 16 Dave> bits being the region number. Correct. >> However, that was shot down pretty hard. Dave> That's unfortunate - it maps really well to how XFS uses Dave> allocation groups. The proposal met a lot of resistance. To the extent that the SMR folks were asked to develop a new command set instead of using the standard SCSI Block Commands. I still think we can get most of what you want out of the static access hints, however. Dave> So the current proposal hides all the physical characteristics of Dave> the devices from the file system and remaps the LBA internally Dave> based on the IO hint? But that is the opposite direction to what Dave> we've been taking over the past couple of years - we want more Dave> visibility of device characteristics at the filesystem level so we Dave> can optimise the filesystem better, not less. The standards bodies are trying to avoid having to special-case handling of shingled drives since they are only a transitional technology with a short life expectancy. We're getting close to the 8-year mark for 4K logical block size transition and it hasn't happened yet. And at this stage it looks like it might not happen at all (in the consumer space at least). So I am not entirely convinced that SMR drives will still be relevant when the standards have been ratified and the filesystems of the world adapted to work with them. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
