[ .... ] >> There are no native 4K sector drives on the market. Linux >> does not support a native 4K sector size, only 512 bytes, >> unless this has changed in recent kernels and I'm simply not >> aware of it yet. > Linux has supported 4k sectors for several years. You can test > it with the scsi_debug module and it's sector_size argument. > The parted test suite has been doing this for a few years to > test that parted correctly handles 1k, 2k, and 4k sector > sizes. Indeed, but 2KiB is a bit theoretical that I don't think any hard disks have 2KiB sectors. The 4KiB sector size transition has been a problem for a 2-3 years after 2009, so that 4KiB hardware sector support is now approximately 5 years old: http://lwn.net/Articles/322777/ «Linux and 4K disk sectors March 11, 2009 [ ... ] Matthew Wilcox recently posted a patch to support 4K sectors according to the ATA-8 standard (PDF). [ ... ]» as the kernel and tools got updated slowly, and it is one reason of the new partition alignment default to 1MB. In the MS-Windows world it is better know as "Advanced Format": http://en.wikipedia.org/wiki/Advanced_Format One of the annoying consequences is that parity-RAID (when not using MD) of with less than 8 data drives would have stripe-let sizes under the common 4KiB filesystem block size, which was exploited cleverly by DDN with their standard 8+2 RAID3 (sort of RAID3...) products. They have switched to another arrangement now that 4KiB drives are fairly common. For MD RAID this did not matter because MD RAID does IO in page cache units, that is base VM pages which on IA32/AMD64 CPUs is 4KiB anyhow, regardless of a smaller physical sector size. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
