Stability and Performance - Oracle WebLogic Server 12c Advanced Administration - page 218

5. Enter :ws! to save the file and exit.
6. Edit the sysctl.conf file under /etc/ :
[root@prod01]$ vi /etc/sysctl.conf
7. Reserve 2048 HugePages by adding the following line:
vm.nr_hugepages = 2048
8. Enter :ws! to save the file and exit.
9. Execute the following command to make the changes effective:
[root@prod01]# sysctl -p
10. Verify the change:
[root@prod01]$ cat /proc/meminfo | grep Huge
HugePages_Total: 2048
HugePages_Free: 2048
HugePages_Rsvd: 0
Hugepagesize: 2048 kB
11. Restart the host if the HugePages could not be allocated.
12. Repeat the preceding steps on all machines in the PROD_DOMAIN .
To enable the Managed Servers to make use of the HugePages, follow the ensuing steps:
1. Access the Administration Console by pointing your web browser to
http://adminhost.domain.local:7001/console .
2. Click on the Lock & Edit button to start a new edit session.
3. Expand the Environment tree to the left and then click on Servers.
4. Click on the PROD_Server01 link and then click on the Server Start tab.
5. Add the following to the Arguments field and click on the Save button:
-XX:+UseLargePagesForHeap
6. Click on the Activate Changes button.
7. Restart PROD_Server01.
8. Repeat the preceding steps for PROD_Server02, PROD_Server03,
and PROD_Server04.
How it works...
The first thing to do is to estimate how much memory should be reserved as HugePages.
Sum all heap sizes of the JVMs in the machine. In our case, we have 2 JVMs with 2 GB each
so a total of 4 GB should be reserved in HugePages.