Re: How to improve db performance with $7K?

Vivek Khera wrote:
>
> On Apr 14, 2005, at 10:03 PM, Kevin Brown wrote:
>
> >Now, bad block remapping destroys that guarantee, but unless you've
> >got a LOT of bad blocks, it shouldn't destroy your performance, right?
> >
>
> ALL disks have bad blocks, even when you receive them.  you honestly
> think that these large disks made today (18+ GB is the smallest now)
> that there are no defects on the surfaces?

Oh, I'm not at all arguing that you won't have bad blocks.  My
argument is that the probability of any given block read or write
operation actually dealing with a remapped block is going to be
relatively small, unless the fraction of bad blocks to total blocks is
large (in which case you basically have a bad disk).  And so the
ability to account for remapped blocks shouldn't itself represent a
huge improvement in overall throughput.




--
Kevin Brown                          kevin@sysexperts.com