大家都知道，數據庫啟動有幾個階段：closed → nomount → mount → open。每個階段都用到了不同的文件，其中：
從closed →nomount 讀取的是spfile或pfile參數文件，在此過程中，分配SGA和后台進程。
從nomount → mount 讀取的是control file控制文件，在mount狀態，可以調整數據庫的歸檔模式，並能做備份和恢復動作。
從mount → open 讀取的是聯機數據文件和redo 文件。
所以當control file出現問題時，數據庫啟動會遇到什么問題，接下來做個試驗：
一、模擬control file丟失環境
（關閉數據庫拷貝控制文件，開啟數據庫執行DML操作后關閉數據庫，備份最新的控制文件，並將舊的控制文件覆蓋到新的控制文件中）
1.1 本數據庫控制文件指定了兩個鏡像，現僅覆蓋其中一個控制文件：
1.1.1 關閉數據庫：
SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. SQL> exit Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options
1.1.2 備份控制文件為control01.ctl.bak、control02.ctl.bak：
[oracle@localhost ~]$ cd /oracle/app/oracle/oradata/ [oracle@localhost oradata]$ ls mydb [oracle@localhost oradata]$ cd mydb/ [oracle@localhost mydb]$ ls control01.ctl example01.dbf redo01.log redo02.log redo04.log system01.dbf temp02.dbf test1.dbf users01.dbf control02.ctl example02.dbf redo0201.log redo03.log sysaux01.dbf temp01.dbf temp03.dbf undotbs02.dbf users02.dbf [oracle@localhost mydb]$ cp control01.ctl control01.ctl.bak [oracle@localhost mydb]$ cp control02.ctl control02.ctl.bak [oracle@localhost mydb]$ ls control01.ctl control02.ctl example01.dbf redo01.log redo02.log redo04.log system01.dbf temp02.dbf test1.dbf users01.dbf control01.ctl.bak control02.ctl.bak example02.dbf redo0201.log redo03.log sysaux01.dbf temp01.dbf temp03.dbf undotbs02.dbf users02.dbf [oracle@localhost mydb]$ cd ~
1.1.3 打開數據庫，進行DML操作：
[oracle@localhost ~]$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.4.0 Production on Fri Feb 23 18:19:14 2018 Copyright (c) 1982, 2013, Oracle. All rights reserved. Connected to an idle instance. SQL> startup ORACLE instance started. Total System Global Area 830930944 bytes Fixed Size 2257800 bytes Variable Size 503319672 bytes Database Buffers 318767104 bytes Redo Buffers 6586368 bytes Database mounted. Database opened. SQL> create table hr.test033002 (test varchar2(10),num int); Table created. SQL> insert into hr.test033002 values('ubin',1); 1 row created. SQL> commit; Commit complete. SQL> update hr.test033002 set test='dftugyoi' where num=1; 1 row updated. SQL> commit; Commit complete.
1.1.4 關閉數據庫：
SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. SQL> exit Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options
1.1.5 備份最新的控制文件為 control01.ctl.bak1、control02.ctl.bak1：
[oracle@localhost ~]$ cd $ORACLE_BASE/oradata/mydb/ [oracle@localhost mydb]$ ls control01.ctl control02.ctl example01.dbf redo01.log redo02.log redo04.log system01.dbf temp02.dbf test1.dbf users01.dbf control01.ctl.bak control02.ctl.bak example02.dbf redo0201.log redo03.log sysaux01.dbf temp01.dbf temp03.dbf undotbs02.dbf users02.dbf [oracle@localhost mydb]$ cp control01.ctl control01.ctl.bak1 [oracle@localhost mydb]$ cp control02.ctl control02.ctl.bak1 [oracle@localhost mydb]$ ls control01.ctl control01.ctl.bak1 control02.ctl.bak example01.dbf redo01.log redo02.log redo04.log system01.dbf temp02.dbf test1.dbf users01.dbf control01.ctl.bak control02.ctl control02.ctl.bak1 example02.dbf redo0201.log redo03.log sysaux01.dbf temp01.dbf temp03.dbf undotbs02.dbf users02.dbf
1.1.6 將第一次備份的控制文件覆蓋，僅覆蓋control.ctl：
[oracle@localhost mydb]$ rm control01.ctl [oracle@localhost mydb]$ cp control01.ctl.bak control01.ctl [oracle@localhost mydb]$ cd ~
1.1.7 此時，登錄sys用戶，執行startup,觀察:
[oracle@localhost mydb]$ cd ~ [oracle@localhost ~]$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.4.0 Production on Fri Feb 23 18:21:58 2018 Copyright (c) 1982, 2013, Oracle. All rights reserved. Connected to an idle instance. SQL> startup ORACLE instance started. Total System Global Area 830930944 bytes Fixed Size 2257800 bytes Variable Size 503319672 bytes Database Buffers 318767104 bytes Redo Buffers 6586368 bytes ORA-00214: control file '/oracle/app/oracle/oradata/mydb/control02.ctl' version 2642138 inconsistent with file '/oracle/app/oracle/oradata/mydb/control01.ctl' version 2642121 SQL> select open_mode from v$database; select open_mode from v$database * ERROR at line 1: ORA-01507: database not mounted
發現在啟動數據庫時，拋出ora-00214報錯，控制文件版本不一致問題，且數據庫狀態為nomount。
1.2 本數據庫控制文件指定了兩個鏡像，現全部覆蓋控制文件：
1.2.1 基於1.1全部操作后續，繼續覆蓋control02.ctl
SQL> shutdown immediate ORA-01507: database not mounted ORACLE instance shut down. SQL> exit Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options [oracle@localhost ~]$ cd $ORACLE_BASE/oradata/mydb [oracle@localhost mydb]$ ls control01.ctl control01.ctl.bak1 control02.ctl.bak example01.dbf redo01.log redo02.log redo04.log system01.dbf temp02.dbf test1.dbf users01.dbf control01.ctl.bak control02.ctl control02.ctl.bak1 example02.dbf redo0201.log redo03.log sysaux01.dbf temp01.dbf temp03.dbf undotbs02.dbf users02.dbf [oracle@localhost mydb]$ rm control02.ctl [oracle@localhost mydb]$ cp control02.ctl.bak control02.ctl [oracle@localhost mydb]$ ls control01.ctl control01.ctl.bak1 control02.ctl.bak example01.dbf redo01.log redo02.log redo04.log system01.dbf temp02.dbf test1.dbf users01.dbf control01.ctl.bak control02.ctl control02.ctl.bak1 example02.dbf redo0201.log redo03.log sysaux01.dbf temp01.dbf temp03.dbf undotbs02.dbf users02.dbf [oracle@localhost mydb]$ cd ~
1.2.2 登錄sys用戶，執行startup 觀察結果：
[oracle@localhost ~]$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.4.0 Production on Fri Feb 23 18:23:10 2018 Copyright (c) 1982, 2013, Oracle. All rights reserved. Connected to an idle instance. SQL> startup ORACLE instance started. Total System Global Area 830930944 bytes Fixed Size 2257800 bytes Variable Size 503319672 bytes Database Buffers 318767104 bytes Redo Buffers 6586368 bytes Database mounted. ORA-01122: database file 1 failed verification check ORA-01110: data file 1: '/oracle/app/oracle/oradata/mydb/system01.dbf' ORA-01207: file is more recent than control file - old control file SQL> select status from v$instance; STATUS ------------------------ MOUNTED
發現在啟動數據庫時，拋出 ORA-01122，ORA-01110，ORA-01207錯誤，且此時數據庫狀態為mount。
二、進行恢復control 控制文件，開啟數據庫
通過mos文檔，可參考文檔：
ORA-1122, ORA-1110, ORA-1207 while open the database after crash (文檔 ID 283927.1)
How to Recreate a Controlfile (文檔 ID 735106.1)
第一步：將數據庫打開至mount狀態
[oracle@localhost ~]$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.4.0 Production on Fri Feb 23 18:52:50 2018 Copyright (c) 1982, 2013, Oracle. All rights reserved. Connected to an idle instance. SQL> startup mount ORACLE instance started. Total System Global Area 830930944 bytes Fixed Size 2257800 bytes Variable Size 503319672 bytes Database Buffers 318767104 bytes Redo Buffers 6586368 bytes Database mounted.
第二步：將控制文件的創建語句放在trace里：
SQL> alter database backup controlfile to trace;
Database altered.
SQL> oradebug setmypid;
Statement processed.
SQL> oradebug tracefile_name;
/oracle/app/oracle/diag/rdbms/mydb/mydb/trace/mydb_ora_7350.trc
第三步：查看trace文件，提取語句
[oracle@localhost ~]$ more /oracle/app/oracle/diag/rdbms/mydb/mydb/trace/mydb_ora_7350.trc Trace file /oracle/app/oracle/diag/rdbms/mydb/mydb/trace/mydb_ora_7350.trc Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options ORACLE_HOME = /oracle/app/oracle/product/11.2.0/dbhome_1 System name: Linux Node name: localhost.localdomain Release: 2.6.32-504.el6.x86_64 Version: #1 SMP Tue Sep 16 01:56:35 EDT 2014 Machine: x86_64 VM name: VMWare Version: 6 Instance name: mydb Redo thread mounted by this instance: 1 Oracle process number: 19 Unix process pid: 7350, image: oracle@localhost.localdomain (TNS V1-V3) *** 2018-02-23 18:57:48.660 *** SESSION ID:(125.3) 2018-02-23 18:57:48.660 *** CLIENT ID:() 2018-02-23 18:57:48.660 *** SERVICE NAME:() 2018-02-23 18:57:48.660 *** MODULE NAME:(sqlplus@localhost.localdomain (TNS V1-V3)) 2018-02-23 18:57:48.660 *** ACTION NAME:() 2018-02-23 18:57:48.660 -- The following are current System-scope REDO Log Archival related -- parameters and can be included in the database initialization file. -- -- LOG_ARCHIVE_DEST='' -- LOG_ARCHIVE_DUPLEX_DEST='' -- -- LOG_ARCHIVE_FORMAT=%t_%s_%r.dbf -- -- DB_UNIQUE_NAME="mydb" -- -- LOG_ARCHIVE_CONFIG='SEND, RECEIVE, NODG_CONFIG' -- LOG_ARCHIVE_MAX_PROCESSES=4 -- STANDBY_FILE_MANAGEMENT=MANUAL -- STANDBY_ARCHIVE_DEST=?/dbs/arch -- FAL_CLIENT='' -- FAL_SERVER='' -- -- LOG_ARCHIVE_DEST_1='LOCATION=/oracle/app/oracle/product/11.2.0/dbhome_1/dbs/arch' -- LOG_ARCHIVE_DEST_1='MANDATORY NOREOPEN NODELAY' -- LOG_ARCHIVE_DEST_1='ARCH NOAFFIRM EXPEDITE NOVERIFY SYNC' -- LOG_ARCHIVE_DEST_1='NOREGISTER NOALTERNATE NODEPENDENCY' -- LOG_ARCHIVE_DEST_1='NOMAX_FAILURE NOQUOTA_SIZE NOQUOTA_USED NODB_UNIQUE_NAME' -- LOG_ARCHIVE_DEST_1='VALID_FOR=(PRIMARY_ROLE,ONLINE_LOGFILES)' -- LOG_ARCHIVE_DEST_STATE_1=ENABLE -- -- Below are two sets of SQL statements, each of which creates a new -- control file and uses it to open the database. The first set opens -- the database with the NORESETLOGS option and should be used only if -- the current versions of all online logs are available. The second -- set opens the database with the RESETLOGS option and should be used -- if online logs are unavailable. -- The appropriate set of statements can be copied from the trace into -- a script file, edited as necessary, and executed when there is a -- need to re-create the control file. -- -- Set #1. NORESETLOGS case -- -- The following commands will create a new control file and use it -- to open the database. -- Data used by Recovery Manager will be lost. -- Additional logs may be required for media recovery of offline -- Use this only if the current versions of all online logs are -- available. -- After mounting the created controlfile, the following SQL -- statement will place the database in the appropriate -- protection mode: -- ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE PERFORMANCE STARTUP NOMOUNT CREATE CONTROLFILE REUSE DATABASE "MYDB" NORESETLOGS ARCHIVELOG MAXLOGFILES 16 MAXLOGMEMBERS 3 MAXDATAFILES 100 MAXINSTANCES 8 MAXLOGHISTORY 584 LOGFILE GROUP 1 '/oracle/app/oracle/oradata/mydb/redo01.log' SIZE 50M BLOCKSIZE 512, GROUP 2 '/oracle/app/oracle/oradata/mydb/redo02.log' SIZE 100M BLOCKSIZE 512, GROUP 3 '/oracle/app/oracle/oradata/mydb/redo03.log' SIZE 50M BLOCKSIZE 512, GROUP 4 '/oracle/app/oracle/oradata/mydb/redo04.log' SIZE 100M BLOCKSIZE 512 -- STANDBY LOGFILE DATAFILE '/oracle/app/oracle/oradata/mydb/system01.dbf', '/oracle/app/oracle/oradata/mydb/sysaux01.dbf', '/oracle/app/oracle/oradata/mydb/users02.dbf', '/oracle/app/oracle/oradata/mydb/users01.dbf', '/oracle/app/oracle/oradata/mydb/example01.dbf', '/oracle/app/oracle/product/11.2.0/dbhome_1/dbs/bigtbs_f2.dbf', '/oracle/app/oracle/oradata/mydb/example02.dbf', '/oracle/app/oracle/oradata/mydb/test1.dbf', '/oracle/app/oracle/oradata/mydb/undotbs02.dbf' CHARACTER SET WE8MSWIN1252 ; -- Commands to re-create incarnation table -- Below log names MUST be changed to existing filenames
第四步：創建生成控制文件的腳本：
[oracle@localhost ~]$ vi control.sql CREATE CONTROLFILE REUSE DATABASE "MYDB" NORESETLOGS ARCHIVELOG MAXLOGFILES 16 MAXLOGMEMBERS 3 MAXDATAFILES 100 MAXINSTANCES 8 MAXLOGHISTORY 584 LOGFILE GROUP 1 '/oracle/app/oracle/oradata/mydb/redo01.log' SIZE 50M BLOCKSIZE 512, GROUP 2 '/oracle/app/oracle/oradata/mydb/redo02.log' SIZE 100M BLOCKSIZE 512, GROUP 3 '/oracle/app/oracle/oradata/mydb/redo03.log' SIZE 50M BLOCKSIZE 512, GROUP 4 '/oracle/app/oracle/oradata/mydb/redo04.log' SIZE 100M BLOCKSIZE 512 -- STANDBY LOGFILE DATAFILE '/oracle/app/oracle/oradata/mydb/system01.dbf', '/oracle/app/oracle/oradata/mydb/sysaux01.dbf', '/oracle/app/oracle/oradata/mydb/users02.dbf', '/oracle/app/oracle/oradata/mydb/users01.dbf', '/oracle/app/oracle/oradata/mydb/example01.dbf', '/oracle/app/oracle/product/11.2.0/dbhome_1/dbs/bigtbs_f2.dbf', '/oracle/app/oracle/oradata/mydb/example02.dbf', '/oracle/app/oracle/oradata/mydb/test1.dbf', '/oracle/app/oracle/oradata/mydb/undotbs02.dbf' CHARACTER SET WE8MSWIN1252 ; ~ ~ "control.sql" [New] 24L, 1015C written
第五步：將數據庫打開到nomount狀態，並執行生成控制文件的腳本：
SQL> startup nomount; ORACLE instance started. Total System Global Area 830930944 bytes Fixed Size 2257800 bytes Variable Size 503319672 bytes Database Buffers 318767104 bytes Redo Buffers 6586368 bytes SQL> @control.sql Control file created
第六步：更改數據庫狀態為open，並查看數據庫狀態和表空間狀態信息：
SQL> alter database open; Database altered. SQL> select status from v$instance; STATUS ------------------------ OPEN SQL> select open_mode from v$database; OPEN_MODE ---------------------------------------- READ WRITE SQL> col TABLESPACE_NAME for a20 SQL> select TABLESPACE_NAME,STATUS,CONTENTS from dba_tablespaces; TABLESPACE_NAME STATUS CONTENTS -------------------- ------------------ ------------------ SYSTEM ONLINE PERMANENT SYSAUX ONLINE PERMANENT TEMP ONLINE TEMPORARY USERS ONLINE PERMANENT UNDOTBS2 ONLINE UNDO EXAMPLE ONLINE PERMANENT BIGTBS_02 ONLINE PERMANENT TBS_TEMP_02 ONLINE TEMPORARY TEMP_DEMO ONLINE TEMPORARY TEST ONLINE PERMANENT 10 rows selected.
此時，數據庫已恢復正常。
其中、mos文檔中還指出，需要創建臨時表空間
ALTER TABLESPACE TEMP_TEST ADD TEMPFILE '/oradata/V11/temp01.dbf' reuse;
這個應該是因情況不同，本次實驗不需要。
暫時記錄到這里啦，接下來可以研究下數據文件丟失時如何恢復。