撥云見日 正確認識password file的作用
（假如沒有口令文件，在數據庫未啟動之前就只能通過操作系統認證）
在我們使用Rman時，許多情況下需要在nomount,mount等狀態下對數據庫進行處理，因此這就要求sysdba權限如果屬于本地DBA組，才可以通過操作系統認證登錄。
（假如是遠程sysdba登錄，需要通過passwordfile認證）
1.remote_login_passwordfile = NONE
在此處我們需要停用口令文件驗證，因為Oracle不允許遠程SYSDBA/SYSOPER身份登錄。
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
大家可以發現，此處是無法通過口令文件驗證的。
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已連接。SQL> show userUSER 為'SYS'SQL>
此處等同于通過口令文件驗證登錄。
3.繼續測試
假如此時我們刪除passwdfile,sysdba/sysoper將會無法認證，從而無法登錄數據庫。
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>
這實際上就是無法通過口令文件驗證身份
4.假如丟失了passwdfile
假如你使用passwdfile后卻意外丟失，那么此時將不能啟動數據庫。
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
我們可以通過orapwd重建口令文件來解決此問題
此處我們恢復口令文件就可以了
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文檔說明:
SHARED
More than one database can use a password file. However, the only user recognized by the password file is SYS.
--多個數據庫可以共享一個口令文件,但是只可以識別一個用戶:SYS
SQL> select * from v$pwfile_users;
USERNAME SYSDB SYSOP
------------------------------ ----- -----
SYS TRUE TRUE
SQL> grant sysdba to eygle;
grant sysdba to eygle
*
ERROR at line 1:
ORA-01994: GRANT failed: cannot add users to public password file
SQL> show parameter password
NAME TYPE VALUE
---------------------- ----------- ----------------------------
remote_login_passwordfile string SHARED
大家可以發現,此時的口令文件中是不能添加用戶的。
很多人可能會問：口令文件的缺省名稱是orapw,如何才能共享?
其實Oracle數據庫在啟動時,首先查找的是orapw的口令文件,假如該文件不存在,則開始查找,orapw的口令文件。如果口令文件命名為orapw,多個數據庫就可以共享。
再來看一下測試:
[oracle@jumper dbs]$ 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,此時可以打開數據庫。
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>
很多人可能會產生有這樣的疑問,多個Exclusive的數據庫是否可以共享一個口令文件(orapw)呢?
繼續回到試驗中:
SQL> show parameter passwordNAME TYPE VALUE
------------------------------------ ----------- ---------------
remote_login_passwordfile string SHARED
[oracle@jumper dbs]$ strings orapw
][Z
ORACLE Remote Password file
INTERNAL
AB27B53EDC5FEF41
8A8F025737A9097A
注意這里僅記錄著INTERNAL/SYS的口令
REMOTE_LOGIN_PASSWORDFILE=EXCLUSIVE 時
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
注意此處,以EXCLUSIVE方式啟動以后,實例名稱信息就會被寫入口令文件.
如果此時有其它實例以Exclusive模式啟動仍然可以使用這個口令文件,口令文件中的實例名稱同時被改寫.
這也就是說,數據庫只在啟動過程中才讀取口令文件,數據庫運行過程中并不鎖定該文件,類似于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：
在此處我們可以增加SYSDBA用戶，并且這些信息可以被寫入到口令文件。
如果我們在口令文件中增加了其他SYSDBA用戶,這個文件就不能被其它Exclusive的實例共享。
仔細了解過后，我們可以發覺，口令文件對于其他用戶來說其實就是啟到了一個sudo的作用。
6.重建口令文件
假如口令文件丟失,使用orapwd可以很方便的重建口令文件，詳細的語法如下:
[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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