Re: Oracle/Solaris Kernel Tunables Question

Connor McDonald <connor_mcdonald_at_yahoo.com> wrote in message news:<3E7FB84C.1A60_at_yahoo.com>...
> Chuck wrote:
> >
> > We are moving from a 4GB Solaris 8 64-bit box to a 10GB box, does it
> > make sense to increase the shmmax parameter?
> >
> > Currently we have:
> > set shmsys:shminfo_shmmax=2097152000
> >
> > Does this line limit the SGA to 2 GB?
> >
> > Thanks,
> > CC
> >
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> It limits the size of a single segment to 2G but Oracle can use multiple
> segments without any great problems. There used to be reports that
> Oracle could not could not use Solaris's ism unless it was in a single
> segment but I'm unsure of the truth of that one
>
> hth
> connor

That's true. See Metalink doc:841636. We recently had this problem on an 8.1.7.4 database and we temporarily set _use_ism=false until next time the server is rebooted for the increased shmsys:shminfo_shmmax to take effect.

Multiple shared memory segments cause instance and each server process startup to slow down a little bit. Other than that (plus the bug with intimate shared memory), there's no harm.

Yong Huang Received on Tue Mar 25 2003 - 12:59:36 CST