Make ZFS use the physical sector size when computing initial ashift

[Xin Li]

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On 07/10/13 02:02, Dag-Erling Sm￸rgrav wrote:
> The attached patch causes ZFS to base the minimum transfer size for
> a new vdev on the GEOM provider's stripesize (physical sector size)
> rather than sectorsize (logical sector size), provided that
> stripesize is a power of two larger than sectorsize and smaller
> than or equal to VDEV_PAD_SIZE.  This should eliminate the need for
> ivoras@'s gnop trick when creating ZFS pools on Advanced Format
> drives.

I think there are multiple versions of this (I also have one[1]) but
the concern is that if one creates a pool with ashift=9, and now
ashift=12, the pool gets unimportable.  So there need a way to disable
this behavior.

Another thing (not really related to the automatic detection) is that
we need a way to manually override this setting from command line when
creating the pool, this is under active discussion at Illumos mailing
list right now.

[1]
https://github.com/trueos/trueos/commit/3d2e3a38faad8df4acf442b055c5e98ab873fb26

Cheers,
- -- 
Xin LI <delphij at delphij.net>    https://www.delphij.net/
FreeBSD - The Power to Serve!           Live free or die
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