ORA-00845: MEMORY_TARGET not supported on this system

Linxu重启后，启动oracle的时候出现下述错误

ORA-00845: MEMORY_TARGET not supported on this system

一般Linux中这个问题是由于SGA的大小超过了操作系统/dev/shm的大小

之前确实是修改过memory_target的参数，但/dev/shm是修改过的。

检查一下：

[root@bjdg01 ~]# df -k /dev/shm

Filesystem 1K-blocks Used Available Use% Mounted on

tmpfs 2028768 0 2028768 0% /dev/shm

发现/dev/shm 显示的值并不是修改过的值，而是没修改前的值。

查看/etc/fstab，发现/dev/shm的值确实是修改后的值，但重启系统后查看/dev/shm显示值却不正确。

# vi /etc/fstab

#

# /etc/fstab

# Created by anaconda on Thu Jan 17 15:46:01 2013

#

# Accessible filesystems, by reference, are maintained under '/dev/disk'

# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

#

UUID=3cffbef8-073b-4236-87d6-8397a525bf41 / ext4 defaults 1 1

UUID=1d2c7310-744f-4de0-adc3-62c7560f71b8 /boot ext4 defaults 1 2

UUID=74da8f6b-5fea-4f09-acd4-94d3b7dd2d94 /tmp ext4 defaults 1 2

UUID=316e2d44-678e-4eed-a872-52abcdd2ed21 swap swap defaults 0 0

tmpfs /dev/shm tmpfs defaults,size=3G 0 0

devpts /dev/pts devpts gid=5,mode=620 0 0

sysfs /sys sysfs defaults 0 0

proc /proc proc defaults 0 0

~

umount后，在mount /dev/shm ,显示正常。

# umount /dev/shm

# mount /dev/shm

# df -k /dev/shm

Filesystem 1K-blocks Used Available Use% Mounted on

tmpfs 3145728 0 3145728 0% /dev/shm

重启Oracle后也正常。

$sqlplus / as sysdba

SQL*Plus: Release 11.2.0.3.0 Production on Wed Feb 27 17:19:14 2013

Copyright (c) 1982, 2011, Oracle. All rights reserved.

Connected to an idle instance.

SQL> startup

ORACLE instance started.

Total System Global Area 3206836224 bytes

Fixed Size 2232640 bytes

Variable Size 2382368448 bytes

Database Buffers 805306368 bytes

Redo Buffers 16928768 bytes

Database mounted.

Database opened.

结论：如果修改了/dev/shm,重启操作系统后要重新mount /dev/shm