Yeah, I'm familiar w/ Bob's paper. Bob actually got it wrong, as you can see if you follow the link to Steve Adams' site that you provided, and actually read what's written there...... -- Mark J. Bobak Senior Oracle Architect ProQuest/CSA "There are 10 types of people in the world: Those who understand binary, and those who don't." ________________________________ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Hameed, Amir Sent: Monday, March 26, 2007 1:31 PM To: Kevin Closson; ax.mount@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx Subject: RE: Solaris 10 shmmax U are probably right Kevin that this feature should not be disabled unless there is an absolute reason not to use it. There was a paper written by Bob Sneed a while ago where he had stated that multiple shared memory segments can impact performance. Steve Adams has also quoted him on his site: http://www.ixora.com.au/q+a/0107/04120647.htm Bob's white paper: http://www.sun.com/blueprints/0101/SunOracle.pdf This may not be an issue anymore. ________________________________ From: Kevin Closson [mailto:kevinc@xxxxxxxxxxxxx] Sent: Monday, March 26, 2007 1:22 PM To: Hameed, Amir; kevinc@xxxxxxxxxxxxx; ax.mount@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx Subject: RE: Solaris 10 shmmax I would also like to understand this a little better. One of my friends is running 10.2.0.2 on Solaris9 and Sun 6900. His shmmax is set to 20G and has 64GB RAM on the server and this is the only instance running on that box. He is seeing multiple shared memory segments on the server. Oracle told him to disable _enable_NUMA_optimization parameter which is enabled by default. ...why? Why turn off the ability for Oracle to exploit the hardware acrchitecture? Is the output of ipcs so disturbing due to multiple segements? That just sounds like concern over nothing.