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Configuring Kernel Parameters for Oracle database server

Posted on June 29th, 2010 in Oracle on Linux Configuring Kernel Parameters during oracle database installation, impact of kernel parameter setting on oracle server, kernel parameters

Impacts of  kernel parameter on oracle server ?

• On SGA(Shared Global area) on oracle server
• Impacts on the total number of users and files in the database
• Impacts the number of users and the ability to use some optional features.

To see all kernel parameters value on your system . execute the following command.

su – root
sysctl -a

List of Kernel Parameters :

shmmax
shmall
shmmni
sem
fs.file-max
fs.aio-max-nr
net.ipv4.ip_local_port_range
net.core.rmem_default
net.core.rmem_max
net.core.wmem_default
net.core.wmem_max

How we can change the Kernel parameters?

If the value of any kernel parameter is different from the recommended value, then change the value to for better performance of the system.
In Linux kernel parameters are stores in the file /etc/sysctl.conf file.
To change the parameters follow the following steps.

1. Edit the file /etc/sysctl.conf
2. Add or edit lines similar to the following

Note :
Include lines only for the kernel parameter values that you want to change.
For the semaphore parameters (kernel.sem), you must specify all four values. However, if any of the current system parameter values are greater than the recommended values, then keep using the larger values.

kernel.shmall = 2097152
kernel.shmmax = 2147483648
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
fs.file-max = 65536
fs.aio-max-nr=1048576
net.ipv4.ip_local_port_range = 1024 65000
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 4194304

Setting kernel parameters value in the  /etc/sysctl.conf file  persist when you restart the system.

Execute following command to effect Kernel changes immediately to server

su – root
sysctl -p

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