ORA-00845: MEMORY_TARGET not supported on this system

来自Oracle的官方解析是：
Starting with Oracle Database 11g, the Automatic Memory Management feature requires more shared memory (/dev/shm)and file descriptors. The size of the shared memory should be at least the greater of MEMORY_MAX_TARGET and MEMORY_TARGET for each Oracle
instance on the computer. If MEMORY_MAX_TARGET or MEMORY_TARGET is set to a non zero value, and an incorrect size is assigned to the shared memory, it will result in an ORA-00845 error at startup.


简单来说就是 MEMORY_MAX_TARGET 的设置不能超过 /dev/shm 的大小：

1[oracle@FWDB FWDB]$ df-h | grepshm 2tmpfs 2.0G 0 2.0G 0% /dev/shm
还真是撞到这个枪口上了：

马上把它加大：

1[root@FWDB ~]# cat /etc/fstab | grep tmpfs2tmpfs /dev/shm tmpfs defaults,size=4G 0 0
现在可以通过重启使这个配置生效，也可以通过重新挂载来修改其大小：

1[root@FWDB ~]# mount -o remount,size=4G /dev/shm2[root@FWDB ~]# df -h | grep shm3tmpfs 4.0G 0 4.0G 0% /dev/shm
再次启动数据库，没有报错了。