Re: Where is the component queue depth actually used in the raidframe system?

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Wed, Mar 13, 2013 at 09:36:07PM -0400, Thor Lancelot Simon wrote:
> On Wed, Mar 13, 2013 at 03:32:02PM -0700, Brian Buhrow wrote:
> >     hello.   What I'm seeing is that the underlying disks under both a
> > raid1 set and a raid5 set are not seeing anymore than 8 active requests at
> > once across the entire bus of disks.  This leaves a lot of disk bandwidth
> > unused, not to mention less than stellar disk performance.  I see that
> > RAIDOUTSTANDING is defined as 6 if not otherwise defined, and this suggests
> > that this is the limiting factor, rather than the actual number of requests
> > allowed to be sent to a component's queue.
> 
> It should be the sum of the number of openings on the underlying components,
> divided by the number of data disks in the set.  Well, roughly.  Getting it
> just right is a little harder than that, but I think it's obvious how.

Actually, I think the simplest correct answer is that it should be the
minimum number of openings presented by any individual underlying component.
I cannot see any good reason why it should be either more nor less than
that value.

Thor