getting to 4K disk blocks in ZFS

[Karl Denninger]

On 9/19/2014 6:23 PM, Steven Hartland wrote:
>
> ----- Original Message -----
>> From: "Justin T. Gibbs" <gibbs at scsiguy.com>
>> To: "Willem Jan Withagen" <wjw at digiware.nl>
>> Cc: "Steven Hartland" <killing at multiplay.co.uk>;
>> <freebsd-stable at freebsd.org>; "Andriy Gapon" <avg at freebsd.org>;
>> "Peter Wemm" <peter at wemm.org>; "Aristedes Maniatis" <ari at ish.com.au>
>> Sent: Saturday, September 20, 2014 12:07 AM
>> Subject: Re: getting to 4K disk blocks in ZFS
>>
>>
>> On Sep 11, 2014, at 5:32 PM, Willem Jan Withagen <wjw at digiware.nl>
>> wrote:
>>
>> > On 11-9-2014 19:49, Peter Wemm wrote:
>> >>> Another downside is 1/4th of uberblocks, 32 vs 128.
>> >>> Also, automatic sector size detection works great for me and I've
>> never had
>> >>> a need to manually tweak ashift.
>> >>
>> >> Unfortunately, I have.  Same drive connected two different ways:
>> >>
>> >> da12 at mps1 bus 0 scbus1 target 11 lun 0
>> >> da12: <ATA ST4000VN000-1H41 SC43> Fixed Direct Access SCSI-6 device
>> >> da12: 600.000MB/s transfers
>> >> da12: Command Queueing enabled
>> >> da12: 3815447MB (7814037168 512 byte sectors: 255H 63S/T 486401C)
>> >>
>> >> ada1 at ahcich1 bus 0 scbus3 target 0 lun 0
>> >> ada1: <ATA ST4000VN000-1H41 SC43> ATA-8 SATA 3.x device
>> >> ada1: 600.000MB/s transfers (SATA 3.x, UDMA6, PIO 8192bytes)
>> >> ada1: Command Queueing enabled
>> >> ada1: 3815447MB (7814037168 512 byte sectors:  16H 63S/T 16383C)
>> >> ada1: quirks=0x1<4K>
>> >>
>> >> The 4k flag is missing when it's on the sas controller.  The Ident
>> strings are
>> >> changed.
>> >>
>> >> This came up elsewhere recently.
>> >
>> > I reported the same fact for the new set of WD REDs I installed.
>> > Seems that ada and da have different quirks tables...
>> > So disks on SATA connectors on the motherboard are diagnosed as
>> being 4Kb.
>> > The disks on my twa don't get the quirk and are considered 512b
>> >
>> > —WjW
>>
>> I’m surprised that we have to constantly add quirks.  Are these
>> drives really
>> failing to report their ata params correctly?  Is there a reason we
>> don’t
>> currently utilize the ata params data (which is already fetched for
>> trim/unmap
>> detection) to also set lbppbe (logical block per physical block
>> exponent) and
>> lalba (lowest aligned lba)?  We may find that many of the existing
>> quirks are
>> unnecessary if we fix the probe code.
>
> On the contary I've not found a single drive which reports 4k sectors
> on its
> own, every single one that I've seen report 4k is because we've added a
> quirk for it :(
>
>
Where is Smartctl getting it from?

smartctl -i /dev/da2
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 ===
Device Model:     HGST HDN724040ALE640
Serial Number:    PK2334PCG6NA0B
LU WWN Device Id: 5 000cca 24cc30684
Firmware Version: MJAOA5E0
User Capacity:    4,000,787,030,016 bytes [4.00 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Form Factor:      3.5 inches
Device is:        Not in smartctl database [for details use: -P showall]
ATA Version is:   ATA8-ACS T13/1699-D revision 4
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Fri Sep 19 18:33:16 2014 CDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled

It's not coming from a database, as Smartctl doesn't know about these
(yet); they're too new.

-- 
Karl Denninger
karl at denninger.net <mailto:karl at denninger.net>
/The Market Ticker/
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