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
