How to work around ORA-00845: MEMORY_TARGET not supported on this system during startup

On Linux platforms, you need to adjust the size of the shared memory file system (/dev/shm) to match the size of your memory_target or memory_max_target. If not you will see the following error:

SQL> startup mount

ORA-00845: MEMORY_TARGET not supported on this system

To adjust the size, open the file /etc/fstab in an editor:

vi /etc/fstab

At the line where you see the tmpfs file system specified, add the size after the keyword "defaults". In the example below, I would like to use a memory_target of 10g, so I add "10g". Do not use a capital letter G, but simply a "g":

tmpfs                   /dev/shm                tmpfs   defaults,size=10g        0 0

Then, remount the file system:

mount –o remount /dev/shm