Post-Install Database Tasks - Oracle Exadata Recipes: A Problem-Solution Approach - page 594

vm.hugetlb_shm_group = 0
vm.nr_hugepages = 25226
[root@cm01dbm01 ~]#

7. When complete, set or validate the database initialization parameter use_large_pages .

The default is TRUE on Oracle 11gR2, which will suffice in most cases. Here are your
options and what they mean:

•

use_large_pages = TRUE will attempt to use HugePages if configured by the operating
system;

•

use_large_pages = FALSE indicates to not use HugePages ;

•

use_large_pages = ONLY means to not start the instance if your HugePages setting is too
small to fit the entire memory footprint of the instance;

•

use_large_pages = AUTO is an 11.2.0.3 feature that will dynamically adjust your
operating system HugePages setting based on the instance you're starting. It will not make
changes to /etc/sysctl.conf but rather dynamically adjust as instances are started.

■ since the compute nodes in an oracle exadata Database Machine run on 64-bit oracle linux, it is not
necessary to set the use_indirect_data_buffers initialization parameter. this is a common misconception that is
discussed in Mos note 361312.1.

Note

8. After validation, you will need to shut down your databases and Oracle CRS on each node.

After your instances are stopped, check your free HugePages from /proc/meminfo :

[root@cm01dbm01 bin]# cat /proc/meminfo|grep Huge
HugePages_Total: 25226
HugePages_Free: 25226
HugePages_Rsvd: 0
Hugepagesize: 2048 kB
[root@cm01dbm01 bin]#

Next, restart your Oracle CRS resources and database instances using crsctl or srvctl .
When complete, again validate /proc/meminfo . When comparing with the output above,
after the restart you should see the number of reserved HugePages ( HugePages_Rsvd ) with
a non-zero number:

9.

[root@cm01dbm01 ~]# cat /proc/meminfo|grep Huge
HugePages_Total: 25226
HugePages_Free: 19122
HugePages_Rsvd: 19104
Hugepagesize: 2048 kB
[root@cm01dbm01 ~]#