Configuring the kernel parameters to install the Oracle database server on CentOS or RedHat

I want to show how to configure the kernel parameters to install the Oracle database server on CentOS or RedHat:


Run the ipcs command with the option -l (list):
ipcs -l

As a result, we can get a list of kernel parameters:

   ------ Shared Memory Limits --------
   max number of segments = 4096                    // SHMMNI  
   max seg size (kbytes) = 32768                       // SHMMAX
   max total shared memory (kbytes) = 3774873      // SHMALL in number of pages
   min seg size (bytes) = 1                 // SHMMIN

   ------ Semaphore Limits --------
   max number of arrays = 1024                         // SEMMNI
   max semaphores per array = 250                      // SEMMSL
   max semaphores system wide = 256000             // SEMMNS
   max ops per semop call = 100                         // SEMOPM
   semaphore max value = 32767

   ------ Messages: Limits --------
   max queues system wide = 1024                       // MSGMNI
   max size of message (bytes) = 65536             // MSGMAX
   default max size of queue (bytes) = 65536       // MSGMNB



Check and set kernel parameters, please.

[Kernel parameter]    [Value]        [Command to check the value]
shmmni            4096        cat /proc/sys/kernel/shmmni
shmall            3774873        cat /proc/sys/kernel/shmall
shmmax            2147483648    cat /proc/sys/kernel/shmmax
shmmin            1        ipcs -lm |grep "min seg size"  
semmsl            250        cat /proc/sys/kernel/sem | awk '{print $1}' 
semmns            256000        cat /proc/sys/kernel/sem | awk '{print $2}' 
semopm            100        cat /proc/sys/kernel/sem | awk '{print $3}' 
semmni            1024        cat /proc/sys/kernel/sem | awk '{print $4}'
file-max        65536        cat /proc/sys/fs/file-max
ip_local_port_range    1024 - 65000    cat /proc/sys/net/ipv4/ip_local_port_range
rmem_default        1048576   
rmem_max        1048576   
wmem_default        262144   
wmem_max        1048576   
aio-max-nr        1048576   
kernel.msgmax        65535   
msgmnb            65535   
Table 1: Kernel parameters of Linux system (e.g. CentOS or RedHat)

Run commands:
su - root
ipcs -ls
sysctl -p
cat /etc/sysctl.conf


Set the following kernel parameters with a option of sysctl command, or in the vi editor:
sysctl -w kernel.sem="250 256000 100 1024"
sysctl -w fs.file-max=65536
or
vi /etc/sysctl.conf
kernel.sem = 250 256000 100 1024
kernel.shmmax=2147483648        # For a 64-bit system
kernel.shmall=3774873        # For 90 percent of 16 GB memory
kernel.msgmax=65535
kernel.msgmnb=65535
net.ipv4.ip_local_port_range = 1024 65000
net.core.rmem_default = 1048576
net.core.rmem_max = 1048576
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
fs.file-max = 65536
fs.aio-max-nr = 1048576

Run sysctl command with -p parameter to load sysctl settings from the default file /etc/sysctl.conf:
sysctl -p
ipcs -ls
reboot
su - root
sysctl -p
ipcs -ls
cat /etc/sysctl.conf

Changes will be effective after every reboot, because of executing of /etc/rc.d/rc.sysinit script
called by /etc/inittab will automatically load /etc/sysctl.conf file.