SQL> show parameter memory
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
hi_shared_memory_address integer 0
memory_max_target big integer 968M
memory_target big integer 968M
shared_memory_address integer 0
alter system set memory_max_target=1200m scope=spfile;
SQL> alter system set memory_max_target=1200m scope=spfile;
System altered.
SQL> alter system set memory_target=1200m scope=spfile;
System altered.
SQL> startup force;
ORA-00845: MEMORY_TARGET not supported on this system
SQL> !df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
21G 17G 2.9G 86% /
tmpfs 1000M 420K 1000M 1% /dev/shm <<<<------------------ increase this value
/dev/sda1 485M 41M 419M 9% /boot
from root
[root@localhost ~]# mount -t tmpfs shmfs -o size=2048m /dev/shm
vi /etc/fstab
/dev/mapper/VolGroup-lv_root / ext4 defaults 1 1
UUID=9a9b0c22-cacf-491c-ad27-b636c69da3cf /boot ext4 defaults 1 2
/dev/mapper/VolGroup-lv_swap swap swap defaults 0 0
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
shmfs /dev/shm tmpfs size=2048m 0 0 <<<<<<<<<---- add following line
then init 6 from reboot <<<<<--- if you can other wise leave
SQL> startup ;
ORACLE instance started.
Total System Global Area 1255473152 bytes
Fixed Size 1344652 bytes
Variable Size 754977652 bytes
Database Buffers 486539264 bytes
Redo Buffers 12611584 bytes
Database mounted.
SQL> show parameter memory
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
hi_shared_memory_address integer 0
memory_max_target big integer 1200M
memory_target big integer 1200M
shared_memory_address integer 0