From: Joe Landman <joe.landman@gmail.com>
To: Carsten Aulbert <Carsten.Aulbert@aei.mpg.de>, stan@hardwarefreak.com
Cc: Phillip Susi <psusi@ubuntu.com>,
joystick <joystick@shiftmail.org>,
linux-raid <linux-raid@vger.kernel.org>
Subject: Re: The chunk size paradox
Date: Thu, 02 Jan 2014 22:14:41 -0500 [thread overview]
Message-ID: <52C62B21.2090609@gmail.com> (raw)
In-Reply-To: <52C5EE8F.3090204@aei.mpg.de>
On 01/02/2014 05:56 PM, Carsten Aulbert wrote:
> Hi
>
> sorry late in joining the thread
Hey Carsten, good to see you here!
>
> On 01/02/2014 11:42 PM, Stan Hoeppner wrote:
>>
>> Damn, you had me salivating Joe. These are both AF 512e drives, not
>> native 4K.
>>
>>> and many others.
>>
>> I've not yet seen an announcement from anyone. I'm not all seeing, but
>> I'd think such an announcement would cross my RADAR.
>>
>
> Just look around:
>
>
> http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771475.pdf
>
> and then the FAQ about "Advanced Format":
>
> https://wdc.custhelp.com/app/answers/detail/a_id/5655
>
> Why would one need to align to 4k if the on disk layout would be 512bytes?
>
> Or did I miss something?
If you align to a 1k size (2x 512 byte emulated sectors), then you will
be offset from the start of the real 4k sector. As you can see from the
WD document, advanced format drives are 4k with a 512byte translation
layer. They are there specifically to provide backwards compatibility
for old OSes. For best performance, they recommend using the units in
their native 4k format.
But they are 4k native and you can use them that way. The 512 byte
layer is emulated.
next prev parent reply other threads:[~2014-01-03 3:14 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
2014-01-03 1:24 ` Stan Hoeppner
2014-01-03 3:14 ` Joe Landman [this message]
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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