Oracle Database 12c install should be installed on CentOS 7 not 6
For CentOS 6, to set kernel parameters, change the file /etc/sysctl.conf and then run:
# sysctl -p
For CentOS 7, add the parameters to a new file called:
/usr/lib/sysctl.d/70-oracledb.conf
Contents:
# Settings for oracle 12c database
# instead of using /etc/sysctl.conf
fs.aio-max-nr = 1048576
fs.file-max = 6815744
#kernel.shmall = 2097152
#kernel.shmmax = 4294967295
#kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
Only activate the kernel.shm arguments if the existing values are lower.
Then reboot.
