vm.nr_hugepages

This is a very quick post to remind users of the importance of large pages. Before 11.2.0.2 it was a little more elaborate process to determine the number of large pages to be set aside for Oracle, but now it’s so simple there isn’t any more excuse not to use large pages. If you have > 16G SGA and lots of processes, check the impact of large pages in /proc/meminfo before and after. By implementing large pages at a former company I reduced the page tables overhead from 20G (60G sga, processes set to 1000, most often around 800 sessions connected) to a fraction of that number.

Here is why you can’t hide anymore: