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From: Rahul on 2 Mar 2010 12:23
John Reiser <jreiserfl(a)comcast.net> wrote in
news:MOedndjz0dfrqxDW4p2dnAA(a)giganews.com:

> 512-byte boundaries. The compensation takes 3 times as long
> (read-modify- write) in contrast to native writes that are aligned to
> 4096 bytes already.

It seems to be killed by writes. I see writes hover around 3 MB/sec. Very
fluctuating. But never over 10 MB/sec.

--
Rahul
From: Grant Edwards on 2 Mar 2010 12:30
On 2010-03-02, Rahul <nospam(a)nospam.invalid> wrote:
> John Reiser <jreiserfl(a)comcast.net> wrote in
> news:MOedndjz0dfrqxDW4p2dnAA(a)giganews.com:
>
>> All drive manufacturers have begun this shift.
>> The physical sector size now is 4096 bytes, instead of the old 512 bytes.
>
> Does that have any silver lining or not at all?

Higher net bit density through reduction of sector overhead.

> Or is it just a manufacturer fad?

--
Grant Edwards grante Yow! This PORCUPINE knows
at his ZIPCODE ... And he has
visi.com "VISA"!!
From: Stan Bischof on 2 Mar 2010 12:37
Rahul <nospam(a)nospam.invalid> wrote:
>> even XP will work if the alignment is wrong: you'll just lose
>> performance.
>
> The nameless "other OS" that I bought this drive earlier was WinServer2008-
> R2. "Lose performance" is an understatement. :) I had to revert to a
> Seagate SAS drive. Hence this project to try and find a home for the
> misbehaving-WD "advanced format" drive.
>
>
>


Are you sure you mean server _2008_ and not _2003_?
2003 is XP-vintage so has issue but 2008 is Vista-vintage
and should not have a problem.

Stan
From: Thad Floryan on 2 Mar 2010 12:50
On 3/2/2010 8:03 AM, John Hasler wrote:
> The drive manufacturers are switching from 512 byte blocks to 4096 byte
> blocks. Windows XP (and, evidently, OSX) can't deal with it so they
> have come up with a kludge. They could have said "If you are using
> Linux don't worry about it" but, being dorks, they didn't. Note that
> even XP will work if the alignment is wrong: you'll just lose
> performance.
>
> Here is a link:
> <http://storagemojo.com/2009/12/21/why-we-need-4k-drives/>

Note there *ARE* Linux issues with these new 4K drives as reported on
Slashdot several weeks ago:

<http://hardware.slashdot.org/story/10/02/14/1541244/Linux-Not-Quite-Ready-For-New-4K-Sector-Drives>

We've seen a few stories recently about the new Western Digital
Green drives:

<http://hardware.slashdot.org/story/06/03/24/0619231/Changes-in-HDD-Sector-Usage-After-30-Years>

According to WD, their new 4096-byte sector drives are problematic
for Windows XP users but not Linux or most other OSes. Linux users
should not be complacent about this, because not all the Linux tools
like fdisk have caught up:

<http://www.osnews.com/story/22872/Linux_Not_Fully_Prepared_for_4096-Byte_Sector_Hard_Drives>

The result is a reduction in write throughput by a factor of 3.3
across the board (a 230% overhead) when 4096-byte clusters are
misaligned to 4096-byte physical sectors by one or more 512-byte
logical sectors. The author does some benchmarks to demonstrate
this. Also, from the comments on the article, it appears that
even parted is not ready, since by default it aligns to 'cylinder'
boundaries, which are not physical cylinder boundaries and are
multiples of 63.
From: Robert Heller on 2 Mar 2010 13:21
At Tue, 2 Mar 2010 16:44:54 +0000 (UTC) Rahul <nospam(a)nospam.invalid> wrote:

>
> John Reiser <jreiserfl(a)comcast.net> wrote in
> news:MOedndjz0dfrqxDW4p2dnAA(a)giganews.com:
>
> > All drive manufacturers have begun this shift.
> > The physical sector size now is 4096 bytes, instead of the old 512 bytes.
>
> Does that have any silver lining or not at all? Or is it just a
> manufacturer fad?

Given the higher and higher bit density, the increase in sector size is
pretty much a given (and probably long overdue). A sector size of 512
was invented for 360K 5.25" *floppies*! And this was an increase from
128 byte sectors on 128K 8" floppies! It is just not cost effective (in
terms of head movement, timing and indexing tracks, disk addressing,
etc.) to deal with an ginormous number of tiny sectors. It is not like
someone is going to get a 1.5 TByte drive and store a ginormous number
of tiny little files on it. Many *modern* file systems are using larger
block sizes in order to deal with larger disks (e[23]fs defaults to a
4096 block size, and so fits right in with a 4096 physical sector size).

>
>

--
Robert Heller -- 978-544-6933
Deepwoods Software -- Download the Model Railroad System
http://www.deepsoft.com/ -- Binaries for Linux and MS-Windows
heller(a)deepsoft.com -- http://www.deepsoft.com/ModelRailroadSystem/

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