环境：

RHEL  6.2  x64

Oracle 11.2.0.1.0

Memory  4G

MEMORY_TARGET=1584M

/dev/shm  2G

 

将MEMORY_TARGET调整为2048M后，重启数据库报错

ORA-00845: MEMORY_TARGET not supported on this system

 

$ oerr ora 84500845, 00000, "MEMORY_TARGET not supported on this system"// *Cause: The MEMORY_TARGET parameter was not supported on this operating system or /dev/shm was not sized correctly on Linux.// *Action: Refer to documentation for a list of supported operating systems. Or, size /dev/shm to be at least the SGA_MAX_SIZE on each Oracle instance running on the system.

 

     这是由于MEMORY_TARGET设置大于/dev/shm，在11g中Oracle引入了MEMORY_TARGET参数管理内存，但这个参数不能大于/dev/shm，否则会报错，Oracle在metalink的文档：Doc ID:Note:460506.1中进行了说明。

解决方法：

1、调整MEMORY_TARGET的大小，使其小于/dev/shm

2、调整/dev/shm的大小，使其大于MEMORY_TARGET

因之前没有做spfile的备份，只能修改/dev/shm的大小，修改如下

# vi /etc/fstab将tmpfs                   /dev/shm               tmpfs   defaults        0 0改为tmpfs                   /dev/shm               tmpfs   defaults,size=4096M        0 0保存退出。# umount /dev/shm# mount /dev/shm

 

再次启动数据库，成功。