Enable Oracle NUMA support with Oracle Server Version 11gR2
(Doc ID 864633.1)
Last updated on OCTOBER 30, 2019
Applies to:Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.
Oracle on NUMA capable hardware
Oracle NUMA (Non Uniform Memory Architecture) support can be used with large SMP multiprocessor environments with NUMA hardware. When enabled Oracle NUMA support facilitates efficient use of underlying NUMA hardware and may improve database performance.
Oracle NUMA support needs the right combination of hardware, operating system and Oracle version.
Starting with 188.8.131.52, Oracle NUMA support is disabled by default.
This note covers how Oracle NUMA support can be enabled via configuration for Oracle Server Version 11.2.
For more information about Oracle NUMA usage recommendation and Oracle NUMA support in previous releases please consult <Note:759565.1>
Care should be taken before enabling NUMA support. Contact your hardware vendor for recommendation and information on your system and operating system NUMA capabilities
- Customers who have tuned their Database specifically for NUMA can continue to run with NUMA enabled with Oracle Server Version 184.108.40.206.
- It is strongly recommended to customers who want to enable NUMA do sufficient testing before going into production.
To enable NUMA support with Oracle Server Version 11gR2 consult the following section "Steps to enable NUMA with Oracle Server Version 11.2”. To disable NUMA on previous versions review <Note 759565.1>
Steps to enable NUMA with Oracle Server Version 11.2:
When running an Oracle database Version 11.2 in a NUMA capable environment, Oracle will not by default detect if the hardware and operating system are NUMA capable and enable Oracle NUMA support.
To enable this capability, the following underscore init.ora parameter need to be set.
No additional steps are required.
This parameter replace and deprecate the init.ora parameter _enable_NUMA_optimization.
If _enable_NUMA_optimization is used instead of _enable_NUMA_support a warning will be displayed in the alert log:
Once the init.ora parameter _enable_NUMA_support is set to TRUE and if the Oracle database version 11.2 runs in a NUMA capable environment, the alert log of the database instance should reflect that NUMA support has been enabled and what NUMA configuration was detected. For example, on a 8 NUMA domains Linux system with 48 cores:
- Disabling or enabling NUMA can change application performance.
- It is strongly recommended to evaluate the performance before and after enabling NUMA in a test environment before going into production.
- Operating system and/or hardware configuration may need to be tuned or reconfigured when disabling Oracle NUMA support. Consult your hardware vendor for more information or recommendation
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