Linux /def/shm related for Oracle 11g Automatic Memory Management

/def/shm does not use /etc/fstab attributes after reboot

There is a bug in Red Hat Linux 6 and Oracle Enterprise Linux 6 (UEK and RHEL-kernel) and probably all other Red Hat 6 related Linux Distro’s.

When you need more memory for SGA/PGA when using MEMORY_MAX_TARGET, you need to resize /dev/shm. By default this is 50% of total memory and Oracle tells you to add the following to /etc/fstab:

shmfs /dev/shm tmpfs size=4g 0 0

Which works…But, there is another line in /etc/fstab which in my opinion should be used and should work:

#tmpfs /dev/shm tmpfs defaults 0 0

tmpfs /dev/shm tmpfs size=4g 0 0

This works after a remount: ‘mount -o remount /dev/shm’,

but it doesn’t work after a reboot…

So  I do the another step with help of Oracle forums and its may be bug of Redhat 6.2,6.1 and OEL 6 Version

https://forums.oracle.com/message/10020717

[root@bl-sms ~]#sudo cp /etc/rc.d/rc.sysinit /etc/rc.d/rc.sysinit.bck

[root@bl-sms ~]#sudo sed -i 's/-f \/dev\/shm/\/dev\/shm/g'

/etc/rc.d/rc.sysinit

 and  then reboot the system

After check the system following command

[root@bl-sms ~]df –h /dev/shm OR

[root@bl-sms ~]df -h

Happy Updating .........