Linux HugePages for Oracle

Few weeks back one DBA told me there is no need to setup HugePages as we are not using 40+GB SGA & we had it enabled from the initial days of 11g migration from 10g (10.2.0.3). Well, here is how you can setup HugePages for your Oracle database instance.

A brief explanation that might help you to decide whether you should enable HugePages or not is quoted from Tim Hall’s article below.

“For large SGA sizes, HugePages can give substantial benefits in virtual memory management. Without HugePages, the memory of the SGA is divided into 4K pages, which have to be managed by the Linux kernel. Using HugePages, the page size is increased to 2MB (configurable to 1G if supported by the hardware), thereby reducing the total number of pages to be managed by the kernel and therefore reducing the amount of memory required to hold the page table in memory. In addition to these changes, the memory associated with HugePages can not be swapped out, which forces the SGA to stay memory resident. The savings in memory and the effort of page management make HugePages pretty much mandatory for Oracle 11g systems running on x86-64 architectures.

Recently I had a short Twitter exchange with Tim Hall about the subject & He mentioned that he always enables it.

Please refer the article from below link, it is by Tim Hall, a geek in this field and the owner of https://oracle-base.com

https://oracle-base.com/articles/linux/configuring-huge-pages-for-oracle-on-linux-64

Exercises explained in this article is applicable to 19c also (verified as working). Please make sure that your version of Oracle database supports these settings before attempting. Please do not copy this to PRODUCTION environments without enough testing.