拨云见日 正确认识password file的作用
（假如没有口令文件，在数据库未启动之前就只能通过操作系统认证）
在我们使用Rman时，许多情况下需要在nomount,mount等状态下对数据库进行处理，因此这就要求sysdba权限如果属于本地DBA组，才可以通过操作系统认证登录。
（假如是远程sysdba登录，需要通过passwordfile认证）
1.remote_login_passwordfile = NONE
在此处我们需要停用口令文件验证，因为Oracle不允许远程SYSDBA/SYSOPER身份登录。
local:
[oracle@jumper oracle]$ sqlplus '/ as sysdba'
SQL*Plus: Release 9.2.0.3.0 - Production on Thu Apr 15 09:58:45 2004
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.3.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.3.0 - Production
SQL> alter user sys identified by oracle;
User altered.
SQL> show parameter pass
NAME TYPE VALUE
--------------------- ----------- ------------------------------
remote_login_passwordfile string NONE
remote:
E:Oracleora92bin>sqlplus /nologSQL*Plus: Release 9.2.0.4.0 -
Production on 星期四 4月 15 09:39:22 2004Copyright (c) 1982, 2002, Oracle
Corporation. All rights reserved.SQL> connect sys/oracle@hsjf as
sysdbaERROR:ORA-01017: invalid username/password; logon denied
大家可以发现，此处是无法通过口令文件验证的。
2.remote_login_passwordfile = exclusive
SQL> alter system set remote_login_passwordfile=exclusive scope=spfile;
System altered.
SQL> startup force;
ORACLE instance started.
Total System Global Area 131142648 bytes
Fixed Size 451576 bytes
Variable Size 104857600 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
Database mounted.
Database opened.
SQL> show parameter pass
NAME TYPE VALUE
------------------------------ ----------- --------------
remote_login_passwordfile string EXCLUSIVE
SQL> alter user sys identified by oracle;
User altered.
remote:
E:Oracleora92bin>sqlplus /nologSQL*Plus: Release 9.2.0.4.0 -
Production on 星期四 4月 15 09:47:11 2004Copyright (c) 1982, 2002, Oracle
Corporation. All rights reserved.SQL> connect sys/oracle@hsjf as
sysdba已连接。SQL> show userUSER 为'SYS'SQL>
此处等同于通过口令文件验证登录。
3.继续测试
假如此时我们删除passwdfile,sysdba/sysoper将会无法认证，从而无法登录数据库。
Server:
SQL> !
[oracle@jumper oracle]$ cd $ORACLE_HOME/dbs
[oracle@jumper dbs]$ ls orapwhsjf
orapwhsjf
[oracle@jumper dbs]$ mv orapwhsjf orapwhsjf.bak
[oracle@jumper dbs]$
Remote:
E:Oracleora92bin>sqlplus /nolog
SQL*Plus: Release 9.2.0.4.0 - Production on 星期四 4月 15 09:50:14 2004
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
SQL> connect sys/oracle@hsjf as sysdba
ERROR:
ORA-01031: insufficient privileges
SQL>
这实际上就是无法通过口令文件验证身份
4.假如丢失了passwdfile
假如你使用passwdfile后却意外丢失，那么此时将不能启动数据库。
SQL> startup force;
ORACLE instance started.
Total System Global Area 131142648 bytes
Fixed Size 451576 bytes
Variable Size 104857600 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
ORA-01990: error opening password file '/opt/oracle/product/9.2.0/dbs/orapw'
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
我们可以通过orapwd重建口令文件来解决此问题
此处我们恢复口令文件就可以了
SQL> !
[oracle@jumper oracle]$ mv $ORACLE_HOME/dbs/orapwhsjf.bak orapwhsjf
[oracle@jumper oracle]$ exit
exit
SQL> alter database open;
Database altered.
SQL>
5. remote_login_passwordfile = shared
Oracle9i文档说明:
SHARED
More than one database can use a password file. However, the only user recognized by the password file is SYS.
--多个数据库可以共享一个口令文件,但是只可以识别一个用户:SYS
SQL> select * from v$pwfile_users;
USERNAME SYSDB SYSOP
------------------------------ ----- -----
SYS TRUE TRUE
SQL> grant sysdba to eygle;
grant sysdba to eygle
*
ERROR at line 1:
ORA-01994: GRANT failed: cannot add users to public password file
SQL> show parameter password
NAME TYPE VALUE
---------------------- ----------- ----------------------------
remote_login_passwordfile string SHARED
大家可以发现,此时的口令文件中是不能添加用户的。
很多人可能会问：口令文件的缺省名称是orapw,如何才能共享?
其实Oracle数据库在启动时,首先查找的是orapw的口令文件,假如该文件不存在,则开始查找,orapw的口令文件。如果口令文件命名为orapw,多个数据库就可以共享。
再来看一下测试:
[oracle@jumper dbs]$ sqlplus '/ as sysdba'
SQL*Plus: Release 9.2.0.3.0 - Production on Tue Jul 6 09:40:34 2004
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.3.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.3.0 - Production
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> !
[oracle@jumper dbs]$ ls
hsjf initdw.ora inithsjf.ora init.ora lkHSJF orapwhsjf spfilehsjf.ora
[oracle@jumper dbs]$ mv orapwhsjf orapwhsjf.bak
[oracle@jumper dbs]$ exit
exit
SQL> startup
ORACLE instance started.
Total System Global Area 235999908 bytes
Fixed Size 451236 bytes
Variable Size 201326592 bytes
Database Buffers 33554432 bytes
Redo Buffers 667648 bytes
ORA-01990: error opening password file '/opt/oracle/product/9.2.0/dbs/orapw'
--它是最后查找的文件
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
建立orapw口令文件,此时可以打开数据库。
SQL> !
[oracle@jumper dbs]$ ls
hsjf initdw.ora inithsjf.ora init.ora lkHSJF orapwhsjf.bak spfilehsjf.ora
[oracle@jumper dbs]$ cp orapwhsjf.bak orapw
[oracle@jumper dbs]$ exit
exit
SQL> alter database open;
Database altered.
SQL> show parameter passw
NAME TYPE VALUE
------------------------------------ ----------- ---------------
remote_login_passwordfile string SHARED
SQL>
很多人可能会产生有这样的疑问,多个Exclusive的数据库是否可以共享一个口令文件(orapw)呢?
继续回到试验中:
SQL> show parameter passwordNAME TYPE VALUE
------------------------------------ ----------- ---------------
remote_login_passwordfile string SHARED
[oracle@jumper dbs]$ strings orapw
][Z
ORACLE Remote Password file
INTERNAL
AB27B53EDC5FEF41
8A8F025737A9097A
注意这里仅记录着INTERNAL/SYS的口令
REMOTE_LOGIN_PASSWORDFILE=EXCLUSIVE 时
SQL> alter system set remote_login_passwordfile=exclusive scope=spfile;System altered.
SQL> startup force;
ORACLE instance started.
Total System Global Area 235999908 bytes
Fixed Size 451236 bytes
Variable Size 201326592 bytes
Database Buffers 33554432 bytes
Redo Buffers 667648 bytes
Database mounted.
Database opened.
SQL> !
[oracle@jumper bin]$ cd $ORACLE_HOME/dbs
[oracle@jumper dbs]$ strings orapw
][Z
ORACLE Remote Password file
HSJF
INTERNAL
AB27B53EDC5FEF41
8A8F025737A9097A
[oracle@jumper dbs]$ exit
exit
注意此处,以EXCLUSIVE方式启动以后,实例名称信息就会被写入口令文件.
如果此时有其它实例以Exclusive模式启动仍然可以使用这个口令文件,口令文件中的实例名称同时被改写.
这也就是说,数据库只在启动过程中才读取口令文件,数据库运行过程中并不锁定该文件,类似于pfile/spfile文件.
SQL> select * from v$pwfile_users;USERNAME SYSDB SYSOP
------------------------------ ----- -----
SYS TRUE TRUE
SQL> grant sysdba to eygle;
Grant succeeded.
SQL> select * from v$pwfile_users;
USERNAME SYSDB SYSOP
------------------------------ ----- -----
SYS TRUE TRUE
EYGLE TRUE FALSE
SQL> !
[oracle@jumper bin]$ cd $ORACLE_HOME/dbs
[oracle@jumper dbs]$ strings orapw
][Z
ORACLE Remote Password file
HSJF
INTERNAL
AB27B53EDC5FEF41
8A8F025737A9097A
>EYGLE
B726E09FE21F8E83
注意：
在此处我们可以增加SYSDBA用户，并且这些信息可以被写入到口令文件。
如果我们在口令文件中增加了其他SYSDBA用户,这个文件就不能被其它Exclusive的实例共享。
仔细了解过后，我们可以发觉，口令文件对于其他用户来说其实就是启到了一个sudo的作用。
6.重建口令文件
假如口令文件丢失,使用orapwd可以很方便的重建口令文件，详细的语法如下:
[oracle@jumper oracle]$ orapwdUsage: orapwd file= password= entries= where
file - name of password file (mand),
password - password for SYS (mand),
entries - maximum number of distinct DBA and OPERs (opt),
There are no spaces around the equal-to (=) character.
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