I've been watching this thread with interest, as some of the posts
contradicted what I thought I knew.

Using nmon, I've watched a couple of systems (AIX, TSM 5.2) running
expiration and DBbackups that have the DB vols set up according to the
"one volume per spindle" premise that appeared to have spotty "hot" disks,
that is the I/O was not distributed evenly across the different volumes.
One drive would have a lot of I/O, then another, etc.

I've always striped them, in hardware if it was available, and using LVM
if it was not.  This gave fairly even I/O, but I admit that doesn't mean
that it was the fastest method.

I'd love to have a definitive answer here, because I've heard it both
ways, and when I've asked support, they didn't seem to know.

I'd like someone "piled higher & deeper" to give a conclusive
answer...anyone?

-Lloyd

On Tue, 24 Jan 2006 14:28:55 -0500
"Allen S. Rout" <asr AT UFL DOT EDU> wrote thusly:

> >> On Tue, 24 Jan 2006 15:43:57 +0100, Dirk Kastens
> ><Dirk.Kastens AT UNI-OSNABRUECK DOT DE> said:
>
> > How do you get the occupancy of a database volume? With Q DBVOL I only
> > see the available space (size of the formatted volume) and the
> > allocated space (what is assigned to the database). In my case both
> > are the same for all volumes.
>
> OK, I'll just blush there.  What I was describing was incorrect.  I've
> got a little space unallocated on all of my databases, for a rainy
> day, and that appearance is similar to what I was describing.
>
> I still think Paul is right, though.  If I wave my hands really hard,
> will that convince you?  Or do I need a Ph.D.?
>
>
> - Allen S. Rout