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30.3. Setting Shared Memory
For Oracle9i installations, the maximum shared memory size must be increased. If it is too small, the Oracle Database Configuration Assistant will display the following error message:
ORA-27123: unable to attach to shared memory segment.
To increase the
shmmaxsetting, execute the following command:
$ su - root # cat /proc/sys/kernel/shmmax 33554432 # echo `expr 1024 \* 1024 \* 1024` > /proc/sys/kernel/shmmax # cat /proc/sys/kernel/shmmax 1073741824
It is recommended to increase the
shmmaxsetting permanently for Oracle. For more information on optimizing shared memory settings for Oracle databases on Linux, see Chapter 7, Setting Shared Memory. These parameters apply to all Red Hat Enterprise Linux versions.