ORA-00845: MEMORY_TARGET not supported on this system

记一次ORACLE启动失败ORA-00845: MEMORY_TARGET not supported on this system

使用oracle用户，像往常一样启动[oracle@localhost ~]$ sqlplus /nologSQL*Plus: Release 11.2.0.1.0 Production on Sun Oct 12 07:07:15 2014Copyright (c) 1982, 2009, Oracle. All rights reserved.SQL> conn /as sysdba
Connected to an idle instance.
SQL>
SQL> startup
ORA-00845: MEMORY_TARGET not supported on this system 呃，问题发生了该怎么办。上网查了下资料，说是MEMORY_MAX_TARGET 的设置不能超过 /dev/shm 的大小。我们来查看下[oracle@localhost ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sdb1 9.5G 2.5G 6.6G 28% /
/dev/sda3 17G 4.6G 12G 29% /home
/dev/sdb2 20G 7.5G 12G 40% /usr/local
/dev/sdc1 30G 174M 28G 1% /opt
/dev/sda1 9.5G 151M 8.9G 2% /tmp
tmpfs 395M 0 395M 0% /dev/shm 这里是395M。按照上面所述，MEMORY_MAX_TARGET将不能超过395M。 我们知道，oracle在startup的时候，可以指定参数。比如可以指定是使用pfile文件还是spfile文件。两者可以相互转换。还有，两者的关系，就是前者是普通的文本文件（可以手动修改），后面是二进制的格式。好，让我们来创建一个pfile文件。SQL> create pfile from spfile;File created.产生的文件将放在ORACLE_HOME/dbs目录下，文件名为initorcl.ora

[oracle@localhost dbs]$ env | grep ORACLE
ORACLE_SID=orcl
ORACLE_BASE=/usr/local/oracle
ORACLE_HOME=/usr/local/oracle/11.2.0[oracle@localhost oracle]$ pwd
/usr/local/oracle
[oracle@localhost oracle]$ cd 11.2.0/dbs/ 进录入dbs目录下，查看一下文件的内容*.memory_target=620756992很明显，大于350M了 修改文件initorcl.ora，改完后的内容如下所示
[oracle@localhost dbs]$ more initorcl.ora
orcl.__db_cache_size=239075328
orcl.__java_pool_size=4194304
orcl.__large_pool_size=4194304
orcl.__oracle_base='/usr/local/oracle'#ORACLE_BASE set from environment
orcl.__pga_aggregate_target=251658240
orcl.__sga_target=369098752
orcl.__shared_io_pool_size=0
orcl.__shared_pool_size=113246208
orcl.__streams_pool_size=0
*.audit_file_dest='/usr/local/oracle/admin/orcl/adump'
*.audit_trail='db'
*.compatible='11.2.0.0.0'
*.control_files='/usr/local/oracle/oradata/orcl/control01.ctl','/usr/local/oracle/oradata/orcl/control02.ctl'
*.db_block_size=8192
*.db_domain='tianjin'
*.db_name='orcl'
*.diagnostic_dest='/usr/local/oracle'
*.dispatchers='(PROTOCOL=TCP) (SERVICE=orclXDB)'
*.memory_target=390M
*.open_cursors=300
*.processes=150
*.remote_login_passwordfile='EXCLUSIVE'
*.undo_tablespace='UNDOTBS1'
[oracle@localhost dbs]$ 这里改为了392M，即小于395M。好，让我们来测试来oracle是否能启动了 SQL> startup pfile=$ORACLE_HOME/dbs/initorcl.ora;
ORACLE instance started.Total System Global Area 410112000 bytes
Fixed Size 1336876 bytes
Variable Size 251660756 bytes
Database Buffers 150994944 bytes
Redo Buffers 6119424 bytes
Database mounted.
Database opened. 呵呵，启动成功了。启动以后的参数
SQL> show parameter mem;NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
hi_shared_memory_address integer 0
memory_max_target big integer 392M
memory_target big integer 392M
shared_memory_address integer 0 好，到目前为止，问题解决了。我们继续往下做实验。例如这里，强行把MEMORY_TARGET设置为大于350M时
SQL> alter system set MEMORY_TARGET=1G;
alter system set MEMORY_TARGET=1G
*
ERROR at line 1:
ORA-02097: parameter cannot be modified because specified value is invalid
ORA-00837: Specified value of MEMORY_TARGET greater than MEMORY_MAX_TARGET 总结：MEMORY_TARGET 不能够大于 MEMORY_MAX_TARGET。此时的MEMORY_MAX_TARGET为392M。 好，强行更改MEMORY_MAX_TARGET为1G时SQL> alter system set MEMORY_MAX_TARGET=1G scope=spfile;
alter system set MEMORY_MAX_TARGET=1G scope=spfile
*
ERROR at line 1:
ORA-32001: write to SPFILE requested but no SPFILE is in use 呃，现在是用pfile模式下启动的总结：使用pfile模式下，不能够通过alter system 来修改参数文件好，那就转成spfile吧 SQL> create spfile from pfile;File created. 使用spfile文件启动后，即startup总结：再次试验，让问题再重现下
SQL> alter system set memory_max_target =1G scope=spfile;System altered.SQL> shutdown abort;
ORACLE instance shut down.
SQL>
SQL> 再次启动
SQL> startup
ORA-00845: MEMORY_TARGET not supported on this system
SQL> 问题又重现了，于是，就有一本文的开始之处。 最后，再做下测试，MEMORY_TARGET和MEMORY_MAX_TARGET两个参数之中，任何一个大于395时，会怎么样呢 设置MEMORY_TARGET为1G时SQL> alter system set memory_target=1G scope=spfile; System altered. 查看spfile文件的变化[oracle@localhost dbs]$ strings spfileorcl.ora*.dispatchers='(PROTOCOL=TCP) (SERVICE=orclXDB)'*.memory_target=1073741824*.open_cursors=300 启动时的报错SQL> startupORA-00845: MEMORY_TARGET not supported on this system 设置MEMORY_MAX_TARGET为1G时 SQL> alter system set memory_max_target =1G scope=spfile;查看文件的变化*.dispatchers='(PROTOCOL=TCP) (SERVICE=orclXDB)'*.memory_max_target=1073741824*.memory_target=390M *.open_cursors=300 这里的memory_target =390M是因为使用pfile时指定的，接着又转成了spfile，没有改过，可以理解为默认值。 启动时的报错。SQL> startupORA-00845: MEMORY_TARGET not supported on this system虽然是memory_max_target大于了395M，而不是memory_target报错而导致，便依然提示MEMORY_TARGET的问题。所以可以总结为，memory_max_target和memory_target中的任何一个出现问题，都将收到MEMORY_TARGET not supported on this system的提示。最后再总结下问题解决的过程从spfile文件创建一个pfile文件修改memory_max_target、memory_target的值startup pfile=$ORACLE_HOME/dbs/initorcl.ora;从pfile文件创建一个spfile文件关闭，再次重启即可 最后，附上参考资料ORACLE的解释Starting with Oracle Database 11g, the Automatic Memory Management feature requires more shared memory (/dev/shm)and file descriptors. The size of the shared memory should be at least the greater of MEMORY_MAX_TARGET and MEMORY_TARGET for each Oracle instance on the computer. If MEMORY_MAX_TARGET or MEMORY_TARGET is set to a non zero value, and an incorrect size is assigned to the shared memory, it will result in an ORA-00845 error at startup.

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