Should root partition be first partition?

Jerry McAllister jerrymc at
Mon Feb 8 20:06:25 UTC 2010

On Mon, Feb 08, 2010 at 02:37:30PM -0500, b. f. wrote:

> > You can even
> >leave gaps between partitions if you want, but that is pretty crazy
> >since it just wastes some of the available space.
> >
> >There have been quite a lot of recommendations on how to lay out a disk
> >for best performance, based on the observation that disk access times
> >vary depending on how far away the data is from the spindle, and the
> >expected usage patterns for the partition.  Like any such advice, it
> >has tended to become less valid over time.  Modern disks really don't
> >have any physical meaning to the Cylinder/Head/Sector style addressing
> >schemes[*] nowadays -- and you're pretty much bound to be using LBA
> >style addressing anyhow.  Also, machines nowadays have so much RAM that
> >(a) swap is hardly ever used and (b) access to popular files is
> >frequently answered out of VM caches rathe than needing disk IO.
> Layout is still important, and leaving some blank space may not be so
> crazy.  Here I'm thinking not so much of ordering (although one would
> probably be best served by the recommended default ordering), but of
> alignment, size, raid/stripe/concat configuration, and file system
> block and fragment size selection.  Witness the (as much as tenfold)
> performance difference from simple changes, highlighted in the recent
> thread entitled 'File system blocks alignment' on freebsd-arch@ during
> December 2009 - January 2010, beginning with:
> If you're laying out a new disk, you may as well take a few minutes
> and get the most out of it, even if you're not going to invest in a
> lot of new hardware.

The system nowdays does all that figuring for you and manages
boundaries reasonably.


> b.
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