HugePages and Oracle Database 11g Automatic Memory Management

When you create a 11g database using Database Configuration Assistant (DBCA), Automatic Memory Management (AMM) is enabled by default. On a Linux system, if AMM is enabled, SGA memory will be allocated by creating files under /dev/shm so HugePages will not be used. Unfortunately AMM is absolutely incompatible with HugePages.

If you want to use HugePages, both MEMORY_TARGET / MEMORY_MAX_TARGET initialization parameters should be unset for the database instance.