fdisk(8) vs gpart(8), and gnop

[Konstantin Belousov]

On Sat, May 31, 2014 at 08:42:42PM -0400, Michael W. Lucas wrote:
> Finally, while UFS isn't picky about changing the underlying sector
> size on a dump/restore, I believe it's a good idea to always gnop the
> underlying disk. Disks lie about sector size, and while it's OK to
> assume a 4k-sector disk, assuming a 512b-sector disk on a 4k-sector
> disk causes write multiplication.
> 
> Are my beliefs correct?

FFS never reads/writes less than the fragment size for the data or
inode access.  Default current setting for newfs is 4K fragment size.
Earlier the fragment size was 2K, AFAIR, but this is irrelevant for
the new disks, unless sector-to-sector copy is performed.

FFS uses cg block size to access cylinder groups, which is definitely
greater than 8K.

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