Status of support for 4KB disk sectors
ivoras at freebsd.org
Tue Jul 19 19:30:19 UTC 2011
On 19.7.2011. 19:54, Chuck Swiger wrote:
> On Jul 18, 2011, at 11:04 PM, Kevin Oberman wrote:
>> I just wish FreeBSD had some decent documentation on such a fundamental
>> operation. Fortunately there are some pretty good articles folks have
>> written, but they did leave me with several questions.
> Is there something in FreeBSD which is preventing you from using the drive's native DEV_BSIZE of 4096 bytes, or is it that the drive claims to have a physical block size of 512 bytes when it is really 4k?
Nope, "only" that.
The current state of the matter (i.e. for 9.0) is:
* The new ATA driver has quirks for certain models of HDDs which have
this false advertising (which can be manually triggered by
kern.cam.ada.X.quirks=1) which causes the drive to report stripesize of 4k.
* This information is used in gpart to size & align partitions; it
will be used by the new installer
* Default fragment size for UFS was raised to 4K so it will be aligned
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