Per Tom Yan suggestion I'm forwarding bug from bugzilla to this ML: https://bugzilla.kernel.org/show_bug.cgi?id=102271 === Dainius Masiliūnas wrote: === When using an Advanced Format drive connected through a SCSI-to-ATA Translation device, the physical block size reported by the kernel (in /sys/class/block/sdc/queue/physical_block_size) is 512 bytes. Whereas hdparm -I and smartctl -a do correctly show the physical block size as 4096 bytes. In my case, the drive in question is a HGST HTS541075A9E680 hard drive, connected to my PC through a USB3 HDD enclosure (USB ID 05e3:0731). While trying to find more information about this issue, I came across someone else's blog post about the same issue I'm having, which includes some in-depth analysis: http://nunix.fr/index.php/linux/7-astuces/65-too-hard-to-be-above-2tb It seems that the kernel uses less reliable means to get details about such devices than hdparm does. I'm using the kernel that's shipped in openSUSE 13.2. === Tom Yan replied: === It is probably because of this: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/storage/scsiglue.c?h=v4.4#n217 SCSI READ CAPACITY (10) will not return "Logical blocks per physical block exponent" like READ CAPACITY (16) does: [tom@localhost ~]$ sudo sg_readcap /dev/sdc Read Capacity results: Last logical block address=468862127 (0x1bf244af), Number of blocks=468862128 Logical block length=512 bytes Hence: Device size: 240057409536 bytes, 228936.6 MiB, 240.06 GB [tom@localhost ~]$ sudo sg_readcap -16 /dev/sdc Read Capacity results: Protection: prot_en=0, p_type=0, p_i_exponent=0 Logical block provisioning: lbpme=0, lbprz=0 Last logical block address=468862127 (0x1bf244af), Number of logical blocks=468862128 Logical block length=512 bytes Logical blocks per physical block exponent=3 [so physical block length=4096 bytes] Lowest aligned logical block address=0 Hence: Device size: 240057409536 bytes, 228936.6 MiB, 240.06 GB -- Pali Rohár pali.rohar@xxxxxxxxx
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