RE: Solaris 10 shmmax

From: Hameed, Amir <Amir.Hameed_at_xerox.com>
Date: Mon, 26 Mar 2007 13:30:57 -0400
Message-ID: <77A4D80DB2ADD74EB5D7F1D31626F0C004F81DC8@usa0300ms03.na.xerox.net>

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_at_polyserve.com] 
	Sent: Monday, March 26, 2007 1:22 PM
	To: Hameed, Amir; kevinc_at_polyserve.com; ax.mount_at_GMAIL.COM;
oracle-l_at_freelists.org
	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.                  

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Received on Mon Mar 26 2007 - 12:30:57 CDT