> -----Original Message-----
> From: owner-freebsd-hackers@free... [mailto:owner-freebsd-hackers@free...] On Behalf Of Tim Kientzle
> Sent: Thursday, May 24, 2012 12:49 AM
> To: Warren Block
> Cc: freebsd-hackers@free...; Matthias Apitz
> Subject: Re: proper newfs options for SSD disk
> GPart's alignment option doesn't work for MBR slices.
> It rounds to the requested alignment, and then rounds again
> to the track size, which defaults to 63 sectors.
> I'm not convinced this is a bug in the design of MBR. I don't
> think anything in the MBR design requires that partitions
> be track-aligned.
It really doesn't. This is old school thinking based around minimizing seek and rotation time on slow multiplatter HDDs. It also helped the redundant superblock layout scheme of UFS make that spiral striping down a set of disk platters. My bet is no one has ever bothered to rethink this in the 25 years since....