一 表空間講解
在上一篇文章(RMAN備份與恢復之控制文件丟失),我們講解了控制文件丟失並且RMAN中有備份怎麼處理,這篇文章講解可脫機數據文件丟失的處理。
表空間是一種邏輯結構,表空間下可以存放數據文件。表空間有系統表空間(SYSTEM)、輔助表空間(SYSAUX)、用戶表空間(USERS)、回退表空間(UNDOTBS1)、臨時表空間(TEMP)、測試表空間(EXAMPLE)、數據表空間。其中系統表空間用於存儲數據字典的信息,不能脫機,不能只讀,也不能改名。輔助表空間用於存儲一些工具以及一些常用的組件,10G開始引入,不能脫機,可以只讀,可以改名。用戶表空間用於存儲用戶數據的表空間,可以脫機,可以只讀,可以改名。回退表空間用於存儲DML操作的事務信息,不能脫機,不能只讀,可以改名。臨時表空間用於存放臨時數據,不能脫機,不能只讀,可以改名。數據表空間用於存放自定義數據,項目中我們一般創建數據表空間,數據存放在數據表空間,這是一種很好的做法,切忌把數據放在默認的USERS表空間。
至於有些表空間可以脫機,有些不可以。那是因爲數據庫在運行期間需要向這些表空間寫入數據,比如系統表空間、輔助表空間、回退表空間、臨時表空間,而用戶表空間、測試表空間、數據表空間不同,只要沒有對這些表空間進行操作,是可以脫機的。
二 備份與恢復可脫機數據文件講解
備份與恢復可脫機數據文件,首先我們要使用RMAN做一個備份全庫的操作,然後模擬USERS表空間丟失,此時我們查看數據會提示數據文件找不到。因爲USERS表空間可以脫機,所以我們可以在SQL Plus中使USERS表空間離線,切記要先離線再進行下面的操作。因爲在RMAN中我們有備份,所以我們可以在RMAN中對USERS表空間對應的數據文件編號進行還原,實際上後臺就行進行了一個拷貝操作。還原成功後,我們需要對USERS表空間對應的數據文件編號進行恢復,等待恢復完成後,再在SQL Plus中使USERS表空間在線,所有的操作完成後,USERS表空間備份與恢復完成,我們可以對數據進行訪問,測試是否恢復成功。需要注意的是,使表空間在線、離線、還原和恢復數據文件一些列的操作切記不要把編號弄錯了,做這些操作應該確認USERS表空間的編號,默認是4號,但是由於後期的修改,USERS表空間數據文件的編號很不能不是4號。作爲DBA,需要時刻保持謹慎!
三 模擬
Step1,RMAN中備份全庫,並在SQL Plus確定數據的正確性
RMAN> BACKUP DATABASE; Starting backup at 12-DEC-13 using channel ORA_DISK_1 channel ORA_DISK_1: starting full datafile backup set channel ORA_DISK_1: specifying datafile(s) in backup set input datafile file number=00001 name=/u01/oracle/oradata/justdb/system01.dbf input datafile file number=00002 name=/u01/oracle/oradata/justdb/sysaux01.dbf input datafile file number=00003 name=/u01/oracle/oradata/justdb/undotbs01.dbf input datafile file number=00004 name=/u01/oracle/oradata/justdb/users01.dbf channel ORA_DISK_1: starting piece 1 at 12-DEC-13 channel ORA_DISK_1: finished piece 1 at 12-DEC-13 piece handle=/u01/oracle/fast_recovery_area/JUSTDB/backupset/2013_12_12/o1_mf_nnndf_TAG20131212T095816_9bl61rrn_.bkp tag=TAG20131212T095816 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:00:25 channel ORA_DISK_1: starting full datafile backup set channel ORA_DISK_1: specifying datafile(s) in backup set including current control file in backup set including current SPFILE in backup set channel ORA_DISK_1: starting piece 1 at 12-DEC-13 channel ORA_DISK_1: finished piece 1 at 12-DEC-13 piece handle=/u01/oracle/fast_recovery_area/JUSTDB/backupset/2013_12_12/o1_mf_ncsnf_TAG20131212T095816_9bl62lw2_.bkp tag=TAG20131212T095816 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01 Finished backup at 12-DEC-13 [oracle@orcl backupset]$ ll 2013_12_12/ total 1025556 -rw------- 1 oracle oinstall 9830400 Dec 12 09:58 o1_mf_ncsnf_TAG20131212T095816_9bl62lw2_.bkp -rw------- 1 oracle oinstall 1040334848 Dec 12 09:58 o1_mf_nnndf_TAG20131212T095816_9bl61rrn_.bkp RMAN> LIST BACKUP; List of Backup Sets =================== BS Key Type LV Size Device Type Elapsed Time Completion Time ------- ---- -- ---------- ----------- ------------ --------------- 14 Full 992.13M DISK 00:00:19 12-DEC-13 BP Key: 14 Status: AVAILABLE Compressed: NO Tag: TAG20131212T095816 Piece Name: /u01/oracle/fast_recovery_area/JUSTDB/backupset/2013_12_12/o1_mf_nnndf_TAG20131212T095816_9bl61rrn_.bkp List of Datafiles in backup set 14 File LV Type Ckp SCN Ckp Time Name ---- -- ---- ---------- --------- ---- 1 Full 1088247 12-DEC-13 /u01/oracle/oradata/justdb/system01.dbf 2 Full 1088247 12-DEC-13 /u01/oracle/oradata/justdb/sysaux01.dbf 3 Full 1088247 12-DEC-13 /u01/oracle/oradata/justdb/undotbs01.dbf 4 Full 1088247 12-DEC-13 /u01/oracle/oradata/justdb/users01.dbf BS Key Type LV Size Device Type Elapsed Time Completion Time ------- ---- -- ---------- ----------- ------------ --------------- 15 Full 9.36M DISK 00:00:01 12-DEC-13 BP Key: 15 Status: AVAILABLE Compressed: NO Tag: TAG20131212T095816 Piece Name: /u01/oracle/fast_recovery_area/JUSTDB/backupset/2013_12_12/o1_mf_ncsnf_TAG20131212T095816_9bl62lw2_.bkp SPFILE Included: Modification time: 12-DEC-13 SPFILE db_unique_name: JUSTDB Control File Included: Ckp SCN: 1088267 Ckp time: 12-DEC-13 SQL> CONN SCOTT/tiger; Connected. SQL> SELECT * FROM tab; TNAME TABTYPE CLUSTERID ------------------------------ ------- ---------- BONUS TABLE DEPT TABLE EMP TABLE SALGRADE TABLE
Step2,SQL Plus中刪除USERS表空間,模擬USERS表空間丟失
SQL> HO mv /u01/oracle/oradata/justdb/users01.dbf /opt/learn/
Step 3,scott用戶查看數據失敗
SQL> CONN SCOTT/tiger; Connected. SQL> DESC dept; ERROR: ORA-01116: error in opening database file 4 ORA-01110: data file 4: '/u01/oracle/oradata/justdb/users01.dbf' ORA-27041: unable to open file Linux-x86_64 Error: 2: No such file or directory Additional information: 3
Step4,SQL Plus中使第4號數據文件離線
SQL> CONN / AS SYSDBA; Connected. SQL> ALTER DATABASE DATAFILE 4 OFFLINE; Database altered.
Step5,RMAN中還原4號數據文件
RMAN> RESTORE DATAFILE 4; Starting restore at 12-DEC-13 using target database control file instead of recovery catalog allocated channel: ORA_DISK_1 channel ORA_DISK_1: SID=1 device type=DISK channel ORA_DISK_1: starting datafile backup set restore channel ORA_DISK_1: specifying datafile(s) to restore from backup set channel ORA_DISK_1: restoring datafile 00004 to /u01/oracle/oradata/justdb/users01.dbf channel ORA_DISK_1: reading from backup piece /u01/oracle/fast_recovery_area/JUSTDB/backupset/2013_12_12/o1_mf_nnndf_TAG20131212T095816_9bl61rrn_.bkp channel ORA_DISK_1: piece handle=/u01/oracle/fast_recovery_area/JUSTDB/backupset/2013_12_12/o1_mf_nnndf_TAG20131212T095816_9bl61rrn_.bkp tag=TAG20131212T095816 channel ORA_DISK_1: restored backup piece 1 channel ORA_DISK_1: restore complete, elapsed time: 00:00:01 Finished restore at 12-DEC-13
Step6,RMAN中恢復4號文件
RMAN> RECOVER DATAFILE 4; Starting recover at 12-DEC-13 using channel ORA_DISK_1 starting media recovery media recovery complete, elapsed time: 00:00:00 Finished recover at 12-DEC-13
Step7,SQL Plus中使4號數據文件在線
SQL> ALTER DATABASE DATAFILE 4 ONLINE; Database altered.
Step8,SQL Plus中查看數據
SQL> CONN SCOTT/tiger; Connected. SQL> DESC dept; Name Null? Type ----------------------------------------- -------- ---------------------------- DEPTNO NOT NULL NUMBER(2) DNAME VARCHAR2(14) LOC VARCHAR2(13) SQL> SELECT * FROM dept; DEPTNO DNAME LOC ---------- -------------- ------------- 10 ACCOUNTING NEW YORK 20 RESEARCH DALLAS 30 SALES CHICAGO 40 OPERATIONS BOSTON
四 相關文章
我的郵箱:[email protected] 新浪微博:@jutdb 微信公衆平臺:JustOracle(微信號:justoracle) 數據庫技術交流羣:336882565(加羣時驗證 From CSDN XXX) All is well 2014年1月15日 By Larry Wen
@Wentasy 博文僅供參考,歡迎大家來訪。如有錯誤之處,希望批評指正。原創博文如需轉載請註明出處,謝謝 :) [CSDN博客] |