From: Phillip Susi <psusi@ubuntu.com>
To: Carsten Aulbert <Carsten.Aulbert@aei.mpg.de>, stan@hardwarefreak.com
Cc: Joe Landman <joe.landman@gmail.com>,
joystick <joystick@shiftmail.org>,
linux-raid <linux-raid@vger.kernel.org>
Subject: Re: The chunk size paradox
Date: Thu, 02 Jan 2014 19:19:51 -0500 [thread overview]
Message-ID: <52C60227.7040809@ubuntu.com> (raw)
In-Reply-To: <52C5EE8F.3090204@aei.mpg.de>
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On 01/02/2014 05:56 PM, Carsten Aulbert wrote:
> Why would one need to align to 4k if the on disk layout would be
> 512bytes?
>
> Or did I miss something?
Because they are providing 512 byte sector emulation on top of 4k
physical sectors. If they were pure 4k sectors, there would be no
need for special alignment. I believe that all WD drives do this, but
I've seen a few people report that some seagate drives skip the 512
emulation. For that matter I have a first generation WD "Green" AF
drive that I am retiring because it has been throwing uncorrectable
errors but not reallocating on write, and often having no problem
reading those sectors later. That drive isn't even nice enough to
report that its really using 4k physical sectors ( despite my requests
for them to fix this firmware bug, they never released an updated
firmware ), though my new blue drives do at least indicate they are 4k
physical.
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next prev parent reply other threads:[~2014-01-03 0:19 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-30 18:48 The chunk size paradox Phillip Susi
2013-12-30 23:38 ` Peter Grandi
2013-12-31 0:01 ` Wolfgang Denk
2013-12-31 13:51 ` David Brown
2014-01-02 20:08 ` Phillip Susi
2014-01-02 14:49 ` joystick
2014-01-02 15:24 ` Phillip Susi
2014-01-02 15:41 ` Stan Hoeppner
2014-01-02 16:31 ` Phillip Susi
2014-01-02 18:02 ` Stan Hoeppner
2014-01-02 19:10 ` Phillip Susi
2014-01-02 22:49 ` Peter Grandi
2014-01-02 23:16 ` Stan Hoeppner
2014-01-03 1:02 ` Phillip Susi
2014-01-02 19:21 ` Joe Landman
2014-01-02 22:42 ` Stan Hoeppner
2014-01-02 22:56 ` Carsten Aulbert
2014-01-03 0:19 ` Phillip Susi [this message]
2014-01-03 1:24 ` Stan Hoeppner
2014-01-03 3:14 ` Joe Landman
2014-01-03 3:19 ` Stan Hoeppner
2014-01-03 4:24 ` Stan Hoeppner
2014-01-02 23:22 ` Peter Grandi
2014-01-03 3:09 ` Joe Landman
2014-01-03 4:58 ` Joe Landman
2014-01-02 22:32 ` Wolfgang Denk
2014-01-03 14:51 ` Benjamin ESTRABAUD
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