Installation guide

The default shared memory limit for SHMMNI can be changed in the proc file system without reboot:

# echo 4096 > /proc/sys/kernel/shmmni

Alternatively, you can use sysctl(8) to change it:

# sysctl -w kernel.shmmni=4096

To make a change permanent, add the following line to the file /etc/sysctl.conf. This file is used during

the boot process.

# echo "kernel.shmmni=4096" >> /etc/sysctl.conf

Setting SHMALL Parameter

This parameter sets the total amount of shared memory, in pages, that the system can use at one time. The de-

fault value of SHMALL can be too small and may cause Oracle database error upon startup (see Metalink

Note:301830.1). Set SHMALL to the total amount of physical RAM divided by page size.

The page size can be determined using the following command:

$ getconf PAGE_SIZE

4096

For 64-bit system with 16GB of RAM and PAGE_SIZE = 4096 the recommended value of SHMALL is 16 *

1024 * 1024 * 1024 / 4096 = 4194304.

To determine the system wide maximum number of shared memory pages, run:

# cat /proc/sys/kernel/shmall

2097152

The shared memory limit for SHMALL can be changed in the proc file system without reboot:

# echo 4194304 > /proc/sys/kernel/shmall

Alternatively, you can use sysctl(8) to change it:

# sysctl -w kernel.shmall=4194304

To make the change permanent, set the value of SHMALL in the /etc/sysctl.conf file:

kernel.shmall=2097152

then run the following command:

# sysctl -p