sql> startup ORA-00845: MEMORY_TARGET not supported on this system Reason: /dev/shm also known as tmpfs i.e. temporary file system which keeps all the file system in virtual memory to speed up several processes. Solution: Increase the size of /dev/shm Check the size of /dev/shm # df -h tmpfs 512M 76K 512M 1% /dev/shm To increase the size # mount -o remount,size=3G /dev/shm Verify the size # df -h tmpfs 3G 1007M 2.1G 33% /dev/shm To make these changes permanent, edit your /etc/fstab file # vi /etc/fstab tmpfs /dev/shm tmpfs defaults,size=3G 0 0 Update the new fstab file # mount -a Startup the oracle instance SQL> startup ORACLE instance started. Total System Global Area 535662592 bytes Fixed Size 1337720 bytes Variable Size 494929544 bytes Database Buffers 33554432 bytes Redo Buffers 5840896 bytes Da