Re: SSD Optimizations

[Stephan von Krawczynski <skraw@ithnet.com>]

On Thu, 11 Mar 2010 15:39:05 +0100
Sander <sander@humilis.net> wrote:

> Stephan von Krawczynski wrote (ao):
> > Honestly I would just drop the idea of an SSD option simply because the
> > vendors implement all kinds of neat strategies in their devices. So in the end
> > you cannot really tell if the option does something constructive and not
> > destructive in combination with a SSD controller.
> 
> My understanding of the ssd mount option is also that the fs doens't try
> to do all kinds of smart (and potential expensive) things which make
> sense for rotating media to reduce seeks and the like.
> 
> 	Sander

Such an optimization sounds valid on first sight. But re-think closely: how
does the fs really know about seeks needed during some operation? If your
disk is a single plate one your seeks are completely different from multi
plate. So even a simple case is more or less unpredictable. If you consider a
RAID or SAN as device base it should be clear that trying to optimize for
certain device types is just a fake. What does that tell you? The optimization
was a pure loss of work hours in the first place. In fact if you look at this
list a lot of talks going on are highly academic and have no real usage
scenario.
Sometimes trying to be super-smart is indeed not useful (for a fs) ...
-- 
Regards,
Stephan