控制文件的备份有两种格式的备份，一种是文本格式的备份另一种是二进制格式的备份
备份文本格式
SQL> alterdatabase backup controlfile to trace as '/bk/con.sql';
Databasealtered.
备份二进制格式
SQL> alterdatabase backup controlfile to trace as '/bk/con.ctl';
Databasealtered.
----加上as字句是为了自定义存储的位置
noresetlog重建控制文件SQL>!cp /etc/passwd /u01/tiger/oradata/orcl2/control01.ctl
SQL> altersystem swirch logfile;
alter systemswirch logfile
*
ERROR at line 1:
ORA-02065:illegal option for ALTER SYSTEM
SQL> altersystem switch logfile;
alter systemswitch logfile
*
ERROR at line 1:
ORA-03113:end-of-file on communication channel
SQL> conn /assysdba
Connected to anidle instance.
SQL> startup
Oracle instancestarted.
Total SystemGlobal Area 314572800 bytes
Fixed Size 1219136 bytes
VariableSize 109053376 bytes
DatabaseBuffers 197132288 bytes
RedoBuffers 7168000 bytes
ORA-00205: errorin identifying control file, check alert log for more info
这里发现当mount的时候发现控制文件有问题，这样我们可以根据之前备份的控制文件的文本文件来恢复控制文件
CREATECONTROLFILE REUSE DATABASE "ORCL2" NORESETLOGS ARCHIVELOG
MAXLOGFILES 16
MAXLOGMEMBERS 3
MAXDATAFILES 100
MAXINSTANCES 8
MAXLOGHISTORY 292
LOGFILE
GROUP 1'/u01/tiger/oradata/orcl2/redo01.log' SIZE 50M,
GROUP 2'/u01/tiger/oradata/orcl2/redo02.log' SIZE 50M,
GROUP 3'/u01/tiger/oradata/orcl2/redo03.log' SIZE50M
DATAFILE
'/u01/tiger/oradata/orcl2/system01.dbf',
'/u01/tiger/oradata/orcl2/tiger.dbf',
'/u01/tiger/oradata/orcl2/sysaux01.dbf',
'/u01/tiger/oradata/orcl2/users01.dbf',
'/u01/tiger/oradata/orcl2/undotbs02.dbf',
'/u01/tiger/oradata/orcl2/undotbs01',
'/u01/tiger/oradata/orcl2/tiger01.dbf'
CHARACTER SETZHS16GBK
SQL> alterdatabase open;
alter databaseopen
*
ERROR at line 1:
ORA-01113: file1 needs media recovery
ORA-01110: datafile 1: '/u01/tiger/oradata/orcl2/system01.dbf'
SQL> recoverdatabase;
Media recoverycomplete.
SQL> alterdatabase open;
Databasealtered.