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Kernel Parameters


Next, we need to check some kernel parameters. Run the following commands, check the output, and make the changes as required.

/sbin/sysctl -a | grep sem
/sbin/sysctl -a | grep shm
/sbin/sysctl -a | grep file-max
/sbin/sysctl -a | grep ip_local_port_range

Output:

kernel.sem = 250 32000 100 128

kernel.shmmni = 4096
kernel.shmall = 2097152
kernel.shmmax = 2147483648

fs.file-max = 65536

net.ipv4.ip_local_port_range = 1024 65000

If you need to change any of the values, open up /etc/sysctl.conf in your favourite text editor (e.g., emacs21) and change the appropriate entries as follows:

kernel.shmall = 2097152
kernel.shmmax = 2147483648
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
fs.file-max = 65536
net.ipv4.ip_local_port_range = 1024 65000

Run /sbin/sysctl -p to apply the changes (only if you changed something of course.)

Add the following lines to /etc/security/limits.conf file:

*               soft    nproc   2047
*               hard    nproc   16384
*               soft    nofile  1024
*               hard    nofile  65536

Add (or un-comment) the following lines in /etc/pam.d/login and /etc/pam.d/su:

session    required     /lib/security/pam_limits.so

Because we are using the Bash shell add the following lines to the /etc/profile file:

if [ $USER = "oracle" ]; then
      if [ $SHELL = "/bin/ksh" ]; then
            ulimit -p 16384
            ulimit -n 65536
      else
            ulimit -u 16384 -n 65536
      fi
fi


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