If you run a Oracle Database on a Linux Server with more than 16 GB physical memory and your System Global Area (SGA) is greater than 8 GB, you should configure HugePages. 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

1. Check Physical Memory

2. Check Database Parameter

3. Check Hugepagesize

4. Calculate Hugepages

For the calculation of the number of hugepages there is a easy way:

SGA / Hugepagesize = Number Hugepages

If you run more than one database on your server, you should include the SGA of all of your instances into the calculation:

( SGA 1. Instance + SGA 2. Instance + … etc. ) / Hugepagesize = Number Hugepages

5. Change Server Configuration

The next parameter is hard and soft memlock in /etc/security/limits.conf for our oracle user. This value should be smaller than our available memory but minor to our SGA

Number Hugepages * Hugepagesize = minimum Memlock

6. Server Reboot

7. Check Configuration

Force Oracle to use HugePages

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