Oracle 11g ORA-00845: MEMORY_TARGET not supported on this system 说明

启动Oracle 11gR2后报错：ORA-00845

rac1:/home/oracle> sqlplus / as sysdba;

SQL*Plus: Release 11.2.0.3.0 Production onTue Feb 14 09:11:41 2012

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

Connected to an idle instance.

SQL> startup

ORA-00845: MEMORY_TARGET not supported onthis system

这个错误之前已经处理过，因为tmpfs的大小MEMORY_TARGET的设置，就会报这种错误。

rac1:/home/oracle> oerr ora 845

00845, 00000, "MEMORY_TARGET notsupported on this system"

// *Cause: The MEMORY_TARGET parameter wasnot supported on this operating system or /dev/shm was not sized correctly onLinux.

// *Action: Refer to documentation for alist of supported operating systems. Or, size /dev/shm to be at least theSGA_MAX_SIZE on each Oracle instance running on the system.

验证一下：

SQL> conn / as sysdba;

Connected to an idle instance.

SQL> startup mount;

ORACLE instance started.

Total System Global Area 1402982400 bytes

Fixed Size 2228304 bytes

Variable Size 822087600 bytes

Database Buffers 570425344 bytes

Redo Buffers 8241152 bytes

Database mounted.

SQL> show parameter memory_target

NAME TYPE VALUE

----------------------------------------------- ------------------------------

memory_target big integer 1344M

--这里的memory_target 有1344M。

[root@rac1 ~]# df -lh

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 14G 11G2.4G 83% /

tmpfs 978M 88K978M 1% /dev/shm

/dev/sda1 194M 46M139M 25% /boot

--这里可以看到tmpfs 只有978M。 这个参数我在安装DB的时候已经修改过：

[root@rac1 ~]# cat /etc/fstab

UUID=b1d2de8e-de31-4deb-b4e8-755c0ed01616/ ext4 defaults 1 1

UUID=4df5aa5f-8ef0-473a-931a-51d11e21aa53/boot ext4 defaults 1 2

UUID=82085104-5021-4aaf-8e85-f213998107b6swap 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

--只是这里的配置在启动的时候没有生效。具体配置参考：

[INS-35172]Target database memory (XXMB) exceeds the systems available shared memory ({0}MB)解决方法

http://blog.csdn.net/tianlesoftware/article/details/6896614

--把tmpfs 重新mount 一下：

[root@rac1 ~]# umount /dev/shm

umount: /dev/shm: device is busy.

(In some cases useful info about processes that use

the device is found by lsof(8) or fuser(1))

Linux umount报device is busy 的处理方法

http://blog.csdn.net/tianlesoftware/article/details/6194295

--设备忙，用fuser处理一下：

[root@rac1 ~]# fuser -km /dev/shm

/dev/shm: 1805m

[root@rac1 ~]# umount /dev/shm

[root@rac1 ~]# mount /dev/shm

[root@rac1 ~]# df -lh

Filesystem Size Used Avail Use% Mounted on

/dev/sda3 14G 11G2.4G 83% /

/dev/sda1 194M 46M139M 25% /boot

tmpfs 3.0G 03.0G 0% /dev/shm

--现在已经正常了。

再次重启了一下，发现发现设置的参数还是没有生效，因此疑惑在Oracle Linux 6.1 下，是否tmpfs始终保持的一半。 这个问题另篇Blog 进行测试。

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