Linux under Install Oracle database parameters Setup

References: 1529864.1
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RAM Swap Space
Between 1 GB and 2 GB 1.5 times the size of RAM
Between 2 GB and GB Equal to the size of RAM
More than GB
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1. Set internal kernel parameters/etc/sysctl.conf
III. Environment:

   1. Below is the minmum Recommended Kernel Parameter settings required for Database software installation. Modify your kernel settings in/etc/sysctl.conf as follows.

Note:if the current value for any parameter is higher than the value listed, does not change the value of that parameter .
Here Note that if the parameters are already larger than the following, do not change the parameters
Kernel.shmall = physical Memory in pages, this would be the value 2097152. See Note 301830.1 for more information. The
parameters are determined by the following
Set shmall equal to the sum of all the Sgas on the system, divided by the page size
that is SHMALL=SGA (BYTES)/page_size
$ getconf page_size
4096
For example, if the sum of a sgas on the system is 16Gb and T He result of  ' $ getconf page_size ' is 4096 (4Kb) then set Shmall to 4194304 pages
This assumes sga=16g
then shmall=16*10 24*1024/4096=4194304
Auto SGA Management set to physical 0.4 (Oracle defaults to physical memory 40%)
Our systems are commonly seen in physical memory by 24GB 32GB
24GB shmall=24*1024*1024*1024*0.4/4096=2516582
32GB shmall=32*1024*1024*1024*0.4 /4096=3355443

Kernel.shmmax = physical Memory in bytes. This would is the value 2147483648 for a system with 4GB of physical RAM.
This is set to half of the physical memory, or slightly larger

For 64-bit Linux Systems:
minimum:536870912 (MB)
Maximum:a value is 1 bytes less than the physical memory
Recommended:more than half the physical memory

See My Oracle Support Note 567506.1 For additional information about configuring Shmmax.

Kernel.shmmni = 4096
Kernel.sem = 250 32000 100 128
Fs.file-max = 6815744
FS.AIO-MAX-NR = 1048576

Note:this value limits concurrent outstanding requests and should is set to avoid I/O subsystem failures.

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

Note:the below Kernel Parameter "Panic_on_oops=1" is being introduced and required from 12.1.0.2.0 onwards.
12.1.0.2.0 the subsequent parameters
Kernel.panic_on_oops=1
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2. Activating the internal core parameters
Sysctl-p
3. Setting User Limits
A)/etc/security/limits.conf
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Use the following:
#<domain> <type> <item> <value>
#<domain> can be:
#-An user name
#-a group name, with @group syntax
#<type> can has the following values:
#-"soft" for enforcing the soft limits
#-' hard ' for enforcing hard limits
#<item> can be one of the following:
#-Nproc-max Number of processes
#-Nofile-max Number of open files
#-Stack-max stack size (KB)
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Oracle Soft Nproc 2047
Oracle Hard Nproc 16384
Oracle Soft Nofile 1024
Oracle Hard Nofile 65536
Oracle Soft Stack 10240
Oracle Hard Stack 10240
Or
@dba Soft Nproc 2047
@dba Hard Nproc 16384
@dba Soft Nofile 4096
@dba Hard Nofile 65536
@dba Soft Stack 10240
@dba Hard Stack 32768
Effective immediately after modification
b)/etc/pam.d/login
Session Required Pam_limits.so
c)/etc/profile
if [$USER = "Oracle"]; Then
if [$SHELL = "/bin/ksh"]; Then
Ulimit-u 16384
Ulimit-n 65536
Else
Ulimit-u 16384-n 65536
Fi
Fi
The 8th point in the text mentions that the default selinux is enforcing, which can no longer be modified as disable in 12c.
8. By default, RHEL 6 x86_64 Linux are installed with SELinux as "enforcing". This is fine for the Oracle Database 12.1 installation process.

Linux under Install Oracle database parameters Setup