When used through a USB-SATA bridge, disk capacity and optimal IO size are reported one sector too less. e.g., with USB-SATA bridge: dmesg: [ 4542.387857] usb 3-1.2: Product: Expansion [ 4542.387871] usb 3-1.2: Manufacturer: Seagate [ 4542.387874] usb 3-1.2: SerialNumber: ******** [ 4542.439329] usbcore: registered new interface driver usb-storage [ 4542.441451] scsi host8: uas [ 4542.442730] scsi 8:0:0:0: Direct-Access Seagate Expansion 9300 PQ: 0 ANSI: 6 [ 4542.444403] usbcore: registered new interface driver uas [ 4542.444635] sd 8:0:0:0: [sdd] Spinning up disk... [ 4543.445400] .....ready [ 4547.458954] sd 8:0:0:0: [sdd] 7814037167 512-byte logical blocks: (4.00 TB/3.64 TiB) fdisk -l: Disk /dev/sdd: 3.7 TiB, 4000787029504 bytes, 7814037167 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 33553920 bytes where the disk size is reported as 7814037168-1 sectors, optimal IO size is 32M-512 bytes. When connected to an SATA port directly: dmesg: [ 1.640249] ata2: SATA link up 6.0 Gbps (SStatus 133 SControl 300) [ 1.643872] ata2.00: ATA-10: ST4000LM024-2AN17V, 0001, max UDMA/133 [ 1.644000] ata2.00: 7814037168 sectors, multi 16: LBA48 NCQ (depth 31/32), AA fdisk -l: Disk /dev/sdb: 4000.8 GB, 4000787030016 bytes 255 heads, 63 sectors/track, 486401 cylinders, total 7814037168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes The disk capacity, 7814037168 sectors, and optimal IO size of 4k bytes look reasonable. Related bug report: https://bugzilla.kernel.org/show_bug.cgi?id=195219 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
