Re: Oracle's max shmseg size on HP-UX

In article <331E3EA6.67F4_at_concentric.net>,   rawoods_at_concentric.net wrote:
>
> Brenda Muller wrote:
> >
> > Hi,
> >
> > I have gotten conflicting reports on the maximum amount of shared
> > memory that Oracle 7.3 can use on HP-UX 10.20. I know the
> > following:
> >
> > - HP-UX will not allow a single shmseg larger than ~1G
> > - HP-UX will not allow a single process to grab more than 2 shmsegs
> > - Oracle will grab one contiguous segment up to ~1G
> > - Oracle will grab two segments if each one < ~500M
> > - Oracle will fail if trying to grab two segments larger than ~500M.
> > This doesn't mean that both were larger than 500M - one could be
> > 520M and the other 200M and it will still fail.
> > - HP-UX will allow a single process to grab two shared memory segments
> > up to a total of 1.75G - each can be up to ~875M.
> >

<snip>

> First of all, what did your Oracle7 7.3 for HP-UX 10.x Installation and
> Configuration Guide specify for shared memory and semaphore settings?
> That information comes from development and the porting groups, the
> folks whom are responsible for determining that information.

These manuals just tell me what to do, without providing any kind of technical justification for their instructions. I need to understand the low-down of what is going on. Actually, I have pretty much proved that there is an HP 2 segment limitation, and an HP 1.75G total shm limitation. And I have been unable to get Oracle to grab more than 1G of shared memory, no matter how I try. And I have tried everything I can think of.

So, what I need to know is if the 1G is an Oracle limitation or not, or rather, is it an Oracle for HP limitation? And if not, what on earth can I do that I haven't already tried to get around this problem?

I don't understand why I've had such a problem trying to get this answer. When I asked HP, they gave me an immediate answer regardingh their limitations.

>
> I believe the 2GB/2 segment SGA cap is HP-specific, as all HP 9000
> platforms look alike to Oracle, from G30's to T520's.

If this was in fact the case, and Oracle had a 2GB/2 segment limitation on HP, I would actually be relatively happy. But as you can see from the points I've listed above, we have been unable to get more than 1G for our SGA.

<snip>

Brenda

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