How set Huge pages in oracle linux RAC.

How set Huge pages in oracle Linux RAC.


Note:==> follow or repeat below steps in each node on RAC.

1.Shutdown all the databases on the host abc-01 and as root user take a backup of /etc/sysctl.conf
2.As root user edit /etc/sysctl.conf and add the below line (setting huge pages  to 190 GB)
vm.nr_hugepages = 97280
3.Edit /etc/sysctl.conf as root user and edit the below line as
kernel.shmmax = 135291469824
This sets the maximum size of single memory segment to 126 gb
After making changes to /etc/sysctl.conf run the below command  as root
sysctl –p
4.Start all the databases on host abc-01
 .
Check that huge pages are in use by running command :
grep Huge /proc/meminfo

Max shared memory configured (16384 Gb) is sufficient to increase sga_max_size for abcdb1
Total shared memory in use is 172 GB

/oracle> ipcs -lm

------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 67108864
max total shared memory (kbytes) = 17179869184
min seg size (bytes) = 1

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