In Oracle Linux 6.3, I have changed my default /dev/shm using
mount -t tmpfs shmfs -o size=3g /dev/shm
And this worked. However I am trying to make the change permanent so I have changed my /etc/fstab entry to be
tmpfs /dev/shm tmpfs size=3g 0 0
However this has not worked. When I reboot my server /dev/shm returns to its original value
Any ideas of how to make the change persist ?
I cannot say what you are trying to accomplish is reasonable, but to the following may solve your problem with the fixed size of POSIX shared memory.