bsdinstall guided partitioning should 4k-align swap and ufs partitions

[Poul-Henning Kamp]

In message <201112051743.13483.Mark.Martinec+freebsd at ijs.si>, Mark Martinec wri
tes:
>Using a guided partitioning install of 9.0-RC2 on a 64GB (virtual) disk
>(from a 9.0-RC2 ISO image) results in the following GPT partitioning:
>
># gpart show /dev/ada0
>=>       34  134217661  ada0  GPT  (64G)
>         34        128     1  freebsd-boot  (64k)
>        162  125828992     2  freebsd-ufs  (60G)
>  125829154    6709248     3  freebsd-swap  (3.2G)
>  132538402    1679293        - free -  (820M)
>
>This is most unfortunate for installations using 4kB sectored disks
>or SSD disks, [...]

This is not a new problem, you face the same issue with RAID5 devices.


GEOM defines two provider properties for handling all these cases
correctly: stripesize + stripeoffset.

If the disk-driver has a 4k drive, or suspects it has a 4k drive (
these properties are advisory only), it should announce that with
the stripe* properties on its GEOM provider.

GEOM classes are responsible for passing these properties up with
whatever adjustments are necessary (for instance modifying the
stripeoffset for partitions).

The partitioning tools, (All of them!) should examine these two
properties and prod the user towards not doing something silly.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.