Implemented following Configuration Changes.
1)SGA_MAX_SIZE=40G
2)SGA_TARGET = 40G
3)PGA_ AGGRIGATE_SIZE=15G
Step 1: Change kernel parameter : Kernel.shmmax (/etc/sysctl.conf)
Kernel.shmmax should be equivalent to SGA_TARGET + PGA_AGGRIGATE_SIZE + 1GB ( for other proces)
Example:
SGA_TARGET + PGA_AGGRIGATGE_SIZE + 1
40G + 15 + 1G (for other process) = 56G / 60129542144
kernel.shmmax = 68719476736 (This value did not change as per the calculated minimum original considerations, as the current value is already a high value by default )
Step 2: Change kernel parameters: Kernel.shmall (/etc/sysctl.conf )
Kernel.shmall should be set to the shmmax values divided by the page size
PAGE SIZE 4k (The standard pagesize on Linux x86_64 is 4096, or 4k)
60129542144 / 4096 = 14680064
Kernel.shmall = 14680064
kernel.shmall = 4294967296 (This value did not change as per the calculated minimum original considerations, as the current value is already a high value by default )
Step 3 : Add kernel parameter for huge page
vm.nr_hugepages is to set to (/etc/sysctl.conf )
60129542144/(2048 * 1024) = 28672
vm.nr_hugepages = 28672
Step 4: Oracle soft memlock and oracle hard memlock should be set to slightly less than the total memory on the server, If memory is 64G. Units are kbytes, so the number is 56000000. This is the total amount of memory Oracle is allowed to lock.
/etc/security/limits.conf
oracle soft memlock 56000000
oracle hard memlock 56000000
Step 5: Following Database parameters configured with below values
SGA_TARGET = 40G
SGA_MAX_SIZE=40G
PGA_AGGRIGATE_SIZE= 15G
All other memory parameter should be disable .
USE_LARGE_PAGES=only
MEMORY_MAX_TARGET=0
MEMORY_TARGET=0
Step 6: In order to verify that hugepages are being used, run this command
[mddsuwldb01:mddprod:/home/oracle:] cat /proc/meminfo
grep Huge
HugePages_Total: 28672
HugePages_Free: XXXX
HugePages_Rsvd: XXXX
Hugepagesize: 2048 kB
