OS version : Red Hat Enterprise Linux Server release 5.5 (Tikanga)
database version :
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
PL/SQL Release 11.2.0.1.0 - Production
CORE 11.2.0.1.0 Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production
现象:修改了spfile文件后,启动数据库报错
oracle#sqlplus / as sysdba
SQL>startup
ORACLE instance started.
Total System Global Area 945786880 bytes
Fixed Size 1340468 bytes
Variable Size 553651148 bytes
Database Buffers 385875968 bytes
Redo Buffers 4919296 bytes
ORA-00845 :MEMORY_TARGET not support on this system
查资料得知:
在oracle 11g中新增的内存自动管理的参数MEMORY_TARGET,它能自动调整SGA和PGA,这个特性需要用到/dev/shm共享文件系统,而且要求/dev/shm必须大于MEMORY_TARGET,如果/dev/shm比MEMORY_TARGET小就会报错
解决方案:
1.初始化参数MEMORY_TARGET或MEMORY_MAX_TARGET不能大于共享内存(/dev/shm),为了解决这个问题,可以增大/dev/shm
如:
# mount -t tmpfs shmfs -o size=7g /dev/shm
2.为了确保操作系统重启之后能生效,需要修改/etc/fstab文件
shmfs /dev/shm tmpfs size=7g 0
3.如果/dev/shm没有挂载也会报上面的错,所认需要确保已经挂载
oracle@aaaprod-db ~]$ df -h
……
tmpfs 16G 8.9G 7.2G 56% /dev/shm
在此启动就ok
SQL> startup
ORACLE instance started.
Total System Global Area 9420095488 bytes
Fixed Size 2236248 bytes
Variable Size 2315255976 bytes
Database Buffers 7046430720 bytes
Redo Buffers 56172544 bytes
Database mounted.
Database opened.
SQL> exit