Page sizes for very high-performance environments

In addition to 4 KB and 64 KB page sizes, AIX® supports 16 MB pages, also called large pages, and 16 GB pages, also called huge pages. These page sizes are intended to be used only in high-performance environments, and AIX will not automatically configure a system to use these page sizes.

AIX must be configured to use these page sizes. The number of pages of each of these page sizes must also be configured. AIX can not automatically change the number of configured 16 MB or 16 GB pages based on demand.

The memory allocated to 16 MB large pages can only be used for 16 MB large pages, and the memory allocated to 16 GB huge pages can only be used for 16 GB huge pages. Thus, pages of these sizes should only be configured in high-performance environments. Also, the use of 16 MB and 16 GB pages is restricted: in order to allocate pages of these sizes, a user must have the CAP_BYPASS_RAC_VMM and CAP_PROPAGATE capabilities, or root authority.