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From: Stan Hoeppner <stan@hardwarefreak.com>
To: Joe Landman <joe.landman@gmail.com>,
	Phillip Susi <psusi@ubuntu.com>,
	joystick <joystick@shiftmail.org>
Cc: linux-raid <linux-raid@vger.kernel.org>
Subject: Re: The chunk size paradox
Date: Thu, 02 Jan 2014 16:42:42 -0600	[thread overview]
Message-ID: <52C5EB62.1090807@hardwarefreak.com> (raw)
In-Reply-To: <52C5BC28.2020003@gmail.com>

On 1/2/2014 1:21 PM, Joe Landman wrote:
> On 01/02/2014 01:02 PM, Stan Hoeppner wrote:
>> On 1/2/2014 10:31 AM, Phillip Susi wrote:
>>> On 1/2/2014 10:41 AM, Stan Hoeppner wrote:
>>>> First, there is no such thing as a 4K sector in Linux.  Sectors are
>>>> 512 bytes.  Filesystem blocks and memory pages are 4K.
>>>
>>> Of course there is.  Disks with 4k sectors are becoming more and more
>>> popular.
>>
>> Please read:  https://en.wikipedia.org/wiki/Advanced_Format
>>
>> There are no native 4K sector drives on the market.  Linux does not
> 
> Untrue.
> 
> http://storage.toshiba.eu/cms/en/hdd/hard_disk_drives/product_detail.jsp?productid=452

From that page:

Physical parameters	
Bytes/sector (Host)		512
Bytes/sector (Disk)		4096 kByte

> 
> http://www.seagate.com/www-content/product-content/constellation-fam/constellation-cs/en-us/docs/terascale-hdd-data-sheet-ds1793-1-1306us.pdf

From that page:

Configuration
Heads/Disks				8/4
Bytes per Sector (512-byte emulation)	4096

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.

> 512 byte sector native drives are now far less common, with many of the
> drives being native 4096 bytes with a translation layer for legacy
> systems that require 512 bytes.  This is infamous for wreaking havoc
> with alignment.

Exactly.  Which is why so many of us wish native 4K drives would be
released.  And, again, AFAIK, nobody is shipping a native drive.
They're all still 512e.  I'd love for someone to prove me wrong here by
pointing one out that is available, preferably more than one.

-- 
Stan



  reply	other threads:[~2014-01-02 22:42 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 [this message]
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
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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