Should root partition be first partition?

b. f. bf1783 at
Mon Feb 8 20:10:39 UTC 2010

On 2/8/10, Jerry McAllister <jerrymc at> wrote:
> 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.
> ////jerry

That does not seem to be the conclusion of those who contributed to
the thread I cited, although "reasonably" is open to interpretation.

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