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Date:      Thu, 31 Dec 2009 17:12:17 +0100
From:      Pieter de Goeje <pieter@degoeje.nl>
To:        freebsd-current@freebsd.org
Cc:        Alexander Motin <mav@freebsd.org>, Miroslav Lachman <000.fbsd@quip.cz>, Thomas Backman <serenity@exscape.org>, freebsd-arch@freebsd.org
Subject:   Re: File system blocks alignment
Message-ID:  <200912311712.18347.pieter@degoeje.nl>
In-Reply-To: <200912281741.27179.pieter@degoeje.nl>
References:  <4B349ABF.2070800@FreeBSD.org> <4B38A4DE.2040507@FreeBSD.org> <200912281741.27179.pieter@degoeje.nl>

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On Monday 28 December 2009 17:41:26 Pieter de Goeje wrote:
> On Monday 28 December 2009 13:30:22 Alexander Motin wrote:
> > Miroslav Lachman wrote:
> > > Alexander Motin wrote:
> > >> Thomas Backman wrote:
> > >>> On Dec 25, 2009, at 11:58 AM, Alexander Motin wrote:
> > >> |>>  Recently WD released first series of ATA disks with increased
> > >>
> > >> physical
> > >>
> > >>>> sector size. It makes writes not matching with 4K blocks inefficie=
nt
> > >>>> there.
> > >>>
> > >>> They don't expose this to the OS, though (not by default, anyway),
> > >>> but chop it up into 8 512-byte sectors for compatibility reasons.
> > >>> Just thought I'd point that out - I'm not even sure if you can get
> > >>> them to *not* do the compatibility thing and expose 4k-sized sector=
s.
> > >>
> > >> Latest ATA-8 specification allows drive to report both logical (512B)
> > >> and physical (4KB) sector sizes. ada driver able to fetch and report
> > >> that info to GEOM. If these drives not reporting it yet (are you
> > >> really sure?), it is only question of their firmware.
> > >
> > > There is an article about 4k sectors
> > > http://www.anandtech.com/storage/showdoc.aspx?i=3D3691
> > >
> > > It is completely hidden to OS in first versions.
> >
> > Thanks for the link, but all I see there is "but at this point there=92s
> > no such tool". IMHO it doesn't meet it is not reported.
> >
> > We just need somebody with that drive to run on it `camcontrol identify`
> > from the fresh system and report what he sees.
>
> I've just ordered one of these disks. I expect it to arrive in a couple of
> days. Will let you know what it says when I have it :)

Ok, as Miroslav wrote, it does not report 4k sectors:

# camcontrol identify ada0
pass0: <WDC WD10EARS-00Y5B1 80.00A80> ATA-8 SATA 2.x device
pass0: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO size 8192bytes)

protocol              ATA/ATAPI-8 SATA 2.x
device model          WDC WD10EARS-00Y5B1
firmware revision     80.00A80
serial number         WD-WCAV55072095
WWN                   50014ee2ae6664fd
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
overlap not supported

=46eature                      Support  Enable    Value           Vendor
read ahead                     yes      yes
write cache                    yes      yes
flush cache                    yes      yes
Native Command Queuing (NCQ)   yes              31/0x1F
Tagged Command Queuing (TCQ)   no       no      31/0x1F
SMART                          yes      yes
microcode download             yes      yes
security                       yes      no
power management               yes      yes
advanced power management      no       no      0/0x00
automatic acoustic management  yes      no      254/0xFE        128/0x80
media status notification      no       no
power-up in Standby            yes      no
write-read-verify              no       no      0/0x0
unload                         no       no
free-fall                      no       no

According to the anandtech article, this is because Windows XP does not wor=
k=20
with sectorsize !=3D 512 bytes.

=2D Pieter



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