ORA-00845: MEMORY_TARGET not supported on this system

启动数据库，报错

idle> startup
ORA-00845: MEMORY_TARGET not supported on this system

原因
/dev/shm的值必须大于或等于memory_target、memory_max_target的值

查看初始化参数文件中memory_target的大小

[oracle@prod1 dbs]$ cat initPROD.ora |grep memory
*.memory_target=1200m

查看临时文件系统的大小

[root@prod1 trace]# df -h /dev/shm/
Filesystem            Size  Used Avail Use% Mounted on
tmpfs                1014M     0 1014M   0% /dev/shm

解决办法
1 提高/dev/shm/

#卸载
[root@prod1 trace]# umount /dev/shm/
umount: /dev/shm: device is busy
umount: /dev/shm: device is busy
#如果卸载失败，杀掉占用该文件系统的进程
[root@prod1 trace]# fuser -km /dev/shm/
#提高大小
[root@prod1 ~]# vi /etc/fstab 
tmpfs                   /dev/shm                tmpfs   defaults,size=1500m        0 0
#重新加载文件系统
[root@prod1 ~]# mount /dev/shm 
#重启数据库
idle> startup
ORACLE instance started.

Total System Global Area 1255473152 bytes
Fixed Size                  1336232 bytes
Variable Size             889195608 bytes
Database Buffers          352321536 bytes
Redo Buffers               12619776 bytes
Database mounted.
Database opened.

2 降低memory_target、memory_max_target的值