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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Alexander Clausen <alex@gc-web.de>
Cc: linux-ide@vger.kernel.org
Subject: Re: 4k sector size and WD20EARS
Date: Thu, 08 Apr 2010 12:02:37 -0400	[thread overview]
Message-ID: <yq17hoix78i.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <4BBDE620.3040601@gc-web.de> (Alexander Clausen's message of "Thu, 08 Apr 2010 16:20:16 +0200")

>>>>> "Alexander" == Alexander Clausen <alex@gc-web.de> writes:

Alexander> Hi, i just bought some WD20EARS harddisk. They are supposed
Alexander> to have 4k physical sector size, right?  My system seems to
Alexander> think they are not:

Alexander> alex@hal:/sys/block/sdb/queue$ cat logical_block_size
Alexander> physical_block_size 512 512 

Alexander> so, who is right?

For unknown reasons these drive report themselves as 512-byte drives
despite using 4096-byte sectors internally.

There really isn't much we can do about devices that don't tell us the
truth.  However, recent fdisk/parted will align on a 1MB boundary by
default which happens do the trick in this particular case (because the
WDC drive is naturally aligned).


Alexander>  1 Primary 0 3907024064 63 3907024065 Linux (83) None
Alexander> alex@hal:~$

Alexander> is that okay for 4k sector size?

No, you should shift the start sector using the fdisk's advanced menu.

-- 
Martin K. Petersen	Oracle Linux Engineering

  reply	other threads:[~2010-04-08 16:03 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-08 14:20 4k sector size and WD20EARS Alexander Clausen
2010-04-08 16:02 ` Martin K. Petersen [this message]
2010-04-08 16:12   ` Mikael Abrahamsson
2010-04-08 16:33     ` Martin K. Petersen
2010-04-08 17:00       ` Mikael Abrahamsson
2010-04-08 18:56         ` Martin K. Petersen
2010-04-08 17:04   ` Alexander Clausen
2010-04-09  2:14     ` Martin K. Petersen
2010-04-12 12:34       ` Karel Zak

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