Re: Increasing the number of semaphores on FreeBSD 4.1 (clarification)

* Philip Hallstrom <philip@adhesivemedia.com> [001109 20:37] wrote:
>
> > * Philip Hallstrom <philip@adhesivemedia.com> [001109 19:12] wrote:
> > > Hi -
> > >     I recently tried to start postmaster (7.0.2) with -B 128 -N 64 and
> > > got the "semget failed" error.  Looking in the faq[1] it says I need to
> > > increase the amount allowed in the kernel.  It tells me what I need to do,
> > > but my question is what values should I set them to?  Is there any way to
> > > figure it out based on load, etc?  Also, are there detrimental effects to
> > > setting them too high?
> >
> > What OS are you using?
>
> FreeBSD 4.1
>
> > > [1]http://postgresql.readysetnet.com/docs/faq-bsdi
> >
> > If it's FreeBSD we've documented the tunables here:
> > http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/i386/conf/NOTES?rev=1.857
> >
> > The docs will probably also help if you're using BSD/os.
> >
> > Also you don't want to "go nuts" with raising these values, they
> > can cause the kernel to allocate too much memory for these structures
> > and cause problems booting or running your system.
>
> Yeah, that's what I've seen... I guess I was wondering if there were any
> guidelines to raising them..  I mean should I up the defaults by 10?  Or
> up them by a percentage (to keep the relationship), etc...

here's what I use:

options         SHMMAXPGS=512000
options         SHMSEG=128
options         SEMMNI=40       #       /* # of semaphore identifiers */
options         SEMMNS=240      #       /* # of semaphores in system */
options         SEMUME=40       #       /* max # of undo entries per process */
options         SEMMNU=120      #       /* # of undo structures in system */

I have a gig of RAM though.

--
-Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org]
"I have the heart of a child; I keep it in a jar on my desk."