illumos gate

Most operating systems no longer attempt to use drive geometry when setting partition boundaries, and instead simply make them megabyte-aligned.
This issue proposes make megabyte-aligned partitions the default, and provide an option (-c) to get the old cylinder-aligned behavior.

Man page addition:

    -c
                          Cylinder alignment.   Make  new  parti-
                          tions  aligned  on cylinders, according
                          to the geometry reported by the device,
                          as  was  common  practice long ago.  By
                          default, format uses the modern conven-
                          tion of aligning partitions on megabyte
                          boundaries.

Just for history, an earlier proposal was:

    -a
                          Align new partitions to 1MB boundaries (default)
    -A
                          Align new  partitions on cylinders, according
                          to the geometry reported by the device,
                          Note that for modern devices that geometry
                          is entirely fictional and can result in partitions
                          that can cause all I/O to be mis-aligned.