Re: 8x2.5" or 6x3.5" disks

Mike Smith wrote:
> I’ve seen a few performance posts on using different hardware
> technologies to gain improvements. Most of those comments are on raid,
>  interface and rotation speed.   One area that doesn’t seem to have
>  been mentioned  is to  run your disks empty.
> ...
> On the outside of the disk you get a lot more data per seek than on the
> inside. Double whammy you get it faster.
>
> Performance  can vary more than  100% between the outer and inner tracks
> of the disk.   So running a slower disk twice as big may give you more
> benefit than running a small capacity 15K disk full.  The slower disks
> are also generally more reliable and mostly much cheaper.
> ...
> This is not very green as you need to buy more disks for the same amount
> of data and its liable to upset your purchasing department who won’t
> understand why you don’t want to fill your disks up.

So presumably the empty-disk effect could also be achieved by partitioning, say 25% of the drive for the database, and
75%empty partition.  But in fact, you could use that "low performance 75%" for rarely-used or static data, such as the
outputfrom pg_dump, that is written during non-peak times. 

Pretty cool.

Craig