getting to 4K disk blocks in ZFS

[Borja Marcos]

On Sep 20, 2014, at 2:06 AM, Gary Palmer wrote:

> If I tell smartctl to ignore it's database it still says it's a 4k

In my case, Samsung 840 EVO SSDs connected to a SAS backplane,

pass6: <Samsung SSD 840 EVO 1TB EXT0BB0Q> ATA-9 SATA 3.x device
pass6: 600.000MB/s transfers, Command Queueing Enabled

protocol              ATA/ATAPI-9 SATA 3.x
device model          Samsung SSD 840 EVO 1TB
firmware revision     EXT0BB0Q
serial number         S1D9NEADA08556K
WWN                   50025388500ae92b
cylinders             16383
heads                 16
sectors/track         63
sector size           logical 512, physical 512, offset 0
LBA supported         268435455 sectors
LBA48 supported       1953525168 sectors
PIO supported         PIO4
DMA supported         WDMA2 UDMA6 
media RPM             non-rotating

even though it has a 4K quirk
da6 at mpr0 bus 0 scbus0 target 30 lun 0
da6: <ATA Samsung SSD 840 BB0Q> Fixed Direct Access SCSI-6 device 
da6: Serial Number S1D9NEADA08556K     
da6: 600.000MB/s transfers
da6: Command Queueing enabled
da6: 953869MB (1953525168 512 byte sectors: 255H 63S/T 121601C)
da6: quirks=0x8<4K>


smartctl reports the same, 512 logical/physical

smartctl 6.3 2014-07-26 r3976 [FreeBSD 10.1-BETA1 amd64] (local build)
Copyright (C) 2002-14, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Samsung based SSDs
Device Model:     Samsung SSD 840 EVO 1TB
Serial Number:    S1D9NEADA08556K
LU WWN Device Id: 5 002538 8500ae92b
Firmware Version: EXT0BB0Q
User Capacity:    1,000,204,886,016 bytes [1.00 TB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    Solid State Device
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ACS-2, ATA8-ACS T13/1699-D revision 4c
SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Mon Sep 22 09:34:24 2014 CEST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
AAM feature is:   Unavailable
APM feature is:   Unavailable
Rd look-ahead is: Enabled
Write cache is:   Enabled
ATA Security is:  Disabled, NOT FROZEN [SEC1]