SuperCluster - OSM ( Optimized Shared Memory ) (12c) is Supported on SuperCluster DISM ( Dynamic Intimate Shared Memory )(11g) is not (Doc ID 1468297.1)

Last updated on FEBRUARY 23, 2017

Applies to:

SPARC SuperCluster T4-4 Full Rack - Version All Versions to All Versions [Release All Releases]
Oracle SuperCluster M6-32 Hardware - Version All Versions to All Versions [Release All Releases]
SPARC SuperCluster T4-4 - Version All Versions to All Versions [Release All Releases]
SPARC SuperCluster T4-4 Half Rack - Version All Versions to All Versions [Release All Releases]
Solaris Operating System - Version 11.3 to 11.3 [Release 11.0]
Oracle Solaris on SPARC (64-bit)

Symptoms

The use of DISM ( Dynamic Intimate Shared Memmory) on the SPARC  SuperCluster including the ASM instance can lead to several different issues ranging form excessive swap usage even when memory is available and expose bugs which can cause kernel panics and/or performance problems.  This led to not being able to take full advantage of AMM (Automatic Memory Management) on SuperCluster. Automatic Memory Management is now possible again with 12.1.0.1 and above database on Oracle Solaris 11.1 SRU 7.5 and above by leveraging the new Optimized Shared Memory (OSM) mechanism.

A dism_chk.sh script is available that can be run as UID 0 root user in any global zone which hosts databases or zones in which databases run.

An example of it's use assuming it is staged in /var/tmp on a GZ in which databases are in fact running....

 

Changes

In 12.1.0.1 and above we now support Optimized Shared Memory (OSM).

In 11.2  and 11.1 any database instance, including the ASM instance, that takes advantage of Automatic Memory Management (AMM) can trigger Dynamic Intimate Shared Memory (DISM) which is bad please see the checks in solution section below. Automatic Shared Memory Management (ASMM) is still supported and recommended.

Cause

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