svn commit: r216230 -
ivoras at freebsd.org
Mon Dec 6 21:23:17 UTC 2010
On 6 December 2010 22:16, Bruce Cran <bruce at cran.org.uk> wrote:
> On Mon, Dec 06, 2010 at 09:31:39PM +0100, Ivan Voras wrote:
>> For what it's worth, apparently linux has the concept of "physical"
>> and "logical" sector sizes (possibly in addition to "stripe size"),
>> with physical being 4096 and logical 512, for example:
>> # hdparm -I /dev/sde | grep size
>> Logical Sector size: 512 bytes
>> Physical Sector size: 4096 bytes
>> device size with M = 1024*1024: 1430799 MBytes
>> device size with M = 1000*1000: 1500301 MBytes (1500 GB)
> So do we, except they're both the same for Advanced Format drives:
There is a subtle difference here which may be important. We have the
concepts of "sectorsize" and "stripesize".
I think camcontrol actually reports logical and physical sector sizes
as reported by low-level drivers but currently GEOM names "logical
sector size" as "sectorsize" and "physical sector size" as
The term "stripesize" can be overloaded to mean both the item in
question - 4 KiB physical sector sizes and RAID stripe sizes. I think
this situation is bad and that the two meanings should be split.
> # camcontrol identify /dev/ada1
> device model WDC WD10EARS-00Z5B1
> sector size logical 512, physical 512, offset 0
Agreed. Some drives lie.
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