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Date:      Wed, 17 Mar 2010 15:17:58 -0300
From:      Thiago Damas <tdamas@gmail.com>
To:        Olivier Smedts <olivier@gid0.org>
Cc:        =?ISO-8859-1?Q?Dag=2DErling_Sm=F8rgrav?= <des@des.no>, Mohacsi Janos <mohacsi@niif.hu>, freebsd-hackers@freebsd.org
Subject:   Re: ATA 4K sector issues
Message-ID:  <f8e3d83f1003171117k20d553b7y7ce4c3c8ed2f5c96@mail.gmail.com>
In-Reply-To: <367b2c981003171112n785ea9d4q21d00b533819ca67@mail.gmail.com>
References:  <alpine.BSF.2.00.1003171114280.74067@mignon.ki.iif.hu>  <86tysf58a2.fsf@ds4.des.no> <alpine.BSF.2.00.1003171652260.74067@mignon.ki.iif.hu>  <f8e3d83f1003171034m5e75eae4r5e8b31d88d361d3b@mail.gmail.com>  <367b2c981003171112n785ea9d4q21d00b533819ca67@mail.gmail.com>

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  I tried with gpart, gpt scheme, begining in all block alignments possible,
34, 35, 36, 37, 38, 39 etc
  Even 64
  gpart create -s gpt ad4
  gpart add -s 64 -t freebsd-zfs ad4

  With UFS, I previouly did some tests (in portuguese):

Particao sem alinhar inicio
=>        34  1953525101  ad4  GPT  (932G)
          34  1953525101    1  freebsd-ufs  (932G)

newfs -U (padrao -f 2048 -b 16384)
# time tar xfj
/install/releases/i386/8.0-RELEASE/8.0-RELEASE/ports/ports.tgz
2.342u 5.013s 20:35.65 0.5%    64+1091k 6623+2734io 0pf+0w

newfs -U -f 4096 -b 32768
# time tar xfj
/install/releases/i386/8.0-RELEASE/8.0-RELEASE/ports/ports.tgz
2.590u 5.263s 22:06.32 0.5%    63+1087k 10911+1676io 0pf+0w


Particao alinhada em multiplos de 4096 bytes (blocos logicos de 512
bytes, entao, multiplo de 8 blocos)
=>        34  1953525101  ad4  GPT  (932G)
          34          30       - free -  (15K)
          64  1953525071    1  freebsd-ufs  (932G)

newfs -U (padrao -f 2048 -b 16384)
# time tar xfj
/install/releases/i386/8.0-RELEASE/8.0-RELEASE/ports/ports.tgz
2.392u 5.000s 10:24.15 1.1%    64+1095k 8375+2735io 0pf+0w

newfs -U -f 4096 -b 32768
# time tar xfj
/install/releases/i386/8.0-RELEASE/8.0-RELEASE/ports/ports.tgz
2.547u 5.567s 1:25.50 9.4%    64+1088k 11880+1755io 0pf+0w



On Wed, Mar 17, 2010 at 3:12 PM, Olivier Smedts <olivier@gid0.org> wrote:

> 2010/3/17 Thiago Damas <tdamas@gmail.com>:
> >  I had problem with ZFS.
> >  With gnop -S 4096, it works well on /dev/ad{a}X.nop; but I decided to
> not
> > use those disks.
>
> So maybe this was not a ZFS problem but a partition misalignment problem ?
>
> On a properly aligned partition with a physical sector size of 4KB and
> a logical sector size of 512 bytes, will ZFS try to use blocksizes of
> less than 4KB ? Blocksize in ZFS seems to be dynamic (at least when
> not told to use a fixed blocksize), but I didn't see somewhere in the
> manpage or Sun's website which minimum blocksize ZFS would use for
> small files, and if there is a lower limit on blocksizes to use.
>
> >
> >
> > 2010/3/17 Mohacsi Janos <mohacsi@niif.hu>
> >
> >>
> >>
> >>
> >> On Wed, 17 Mar 2010, Dag-Erling Sm?rgrav wrote:
> >>
> >>  Mohacsi Janos <mohacsi@niif.hu> writes:
> >>>
> >>>> What is the situation with ATA 4K dirves in FreeBSD? Are there
> >>>> any support for them in fdisk or disklabel?
> >>>>
> >>>
> >>> Hmm, didn't we discuss this already?  All we need to do is change the
> >>> defaults in fdisk so it rounds partition offsets and sizes to a
> multiple
> >>> of 8 sectors (or 16 for future-proofing) instead of aligning them with
> >>> fictitious cylinder boundaries.  Bsdlabel, as disklabel is properly
> >>> known, already DTRT: by default, the first partition starts at offset
> >>> 16.  Just make sure you specify sizes that are divisible by 8 or 16
> >>> blocks (not an issue if you use the M or G suffixes).  Sysinstall
> >>> operates in megabytes.
> >>>
> >>
> >> Thanks for the information.
> >>
> >>
> >> _______________________________________________
> >> freebsd-hackers@freebsd.org mailing list
> >> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
> >> To unsubscribe, send any mail to "
> freebsd-hackers-unsubscribe@freebsd.org"
> >>
> > _______________________________________________
> > freebsd-hackers@freebsd.org mailing list
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> > To unsubscribe, send any mail to "
> freebsd-hackers-unsubscribe@freebsd.org"
> >
>
>
>
> --
> Olivier Smedts                                                 _
>                                        ASCII ribbon campaign ( )
> e-mail: olivier@gid0.org        - against HTML email & vCards  X
> www: http://www.gid0.org    - against proprietary attachments / \
>
>  "Il y a seulement 10 sortes de gens dans le monde :
>  ceux qui comprennent le binaire,
>  et ceux qui ne le comprennent pas."
>



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