Oracle备份与恢复策略介绍(4)

2019-04-14 22:39

RMAN-08024: channel c1: restore complete

RMAN-03023: executing command: partial resync

RMAN-08003: starting partial resync of recovery catalog RMAN-08005: partial resync complete RMAN-03022: compiling command: recover RMAN-03022: compiling command: recover(1) RMAN-03022: compiling command: recover(2) RMAN-03022: compiling command: recover(3) RMAN-03023: executing command: recover(3) RMAN-08054: starting media recovery

RMAN-03022: compiling command: recover(4)

RMAN-06050: archivelog thread 1 sequence 327 is already D:\\Oracle\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00327.ARC

RMAN-06050: archivelog thread 1 sequence 328 is already D:\\Oracle\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00328.ARC

RMAN-06050: archivelog thread 1 sequence 329 is already D:\\Oracle\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00329.ARC

RMAN-06050: archivelog thread 1 sequence 330 is already D:\\Oracle\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00330.ARC RMAN-03023: executing command: recover(4) RMAN-08515:

filename=D:\\Oracle\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00327.ARC sequence=327 RMAN-08515:

filename=D:\\Oracle\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00328.ARC sequence=328

RMAN-08055: media recovery complete RMAN-03022: compiling command: sql

RMAN-06162: sql statement: alter database open RMAN-03023: executing command: sql

RMAN-03022: compiling command: release RMAN-03023: executing command: release RMAN-08031: released channel: c1 RMAN>

on disk as file on disk as file on disk as file on disk as file

archivelog thread=1 archivelog thread=1

7、 检查数据库的数据(完全恢复)

SQL> select * from test; A

--------------------------------------- 1 2

说明:

1、只要有备份与归档存在,RMAN也可以实现数据库的完全恢复(不丢失数据);

2、同OS备份数据库恢复,适合于丢失大量数据文件,或包含系统数据文件在内的数据库的恢

复;

3、目标数据库在mount下进行,如果恢复成功,再打开数据库;

4、RMAN的备份与恢复命令相对比较简单并可靠,建议有条件的话,都采用RMAN进行数据库

的备份。

4.4 不完全恢复案例

4.4.1 OS备份下的基于时间的恢复

不完全恢复可以分为基于时间的恢复,基于改变的恢复与基于撤消的恢复,这里已基于时间的恢复为例子来说明不完全恢复过程。

基于时间的恢复可以不完全恢复到现在时间之前的某一个时间,对于某些误操作,如删除了一个数据表,可以在备用恢复环境上恢复到表的删除时间之前,然后把该表导出到正式环境,避免一个人为的错误。

1、 连接数据库,创建测试表并插入记录:

SQL> connect internal/password as sysdba; Connected.

SQL> create table test(a int); Table created

SQL> insert into test values(1); 1 row inserted SQL> commit; Commit complete

2、 备份数据库,这里最好备份所有的数据文件,包括临时数据文件:

SQL> @hotbak.sql 或在DOS下 svrmgrl @hotbak.sql 或冷备份也可以

3、 删除测试表,假定删除前的时间为T1,在删除之前,便于测试,继续插入数据并应用到归

档。

SQL> insert into test values(2); 1 row inserted SQL> commit; Commit complete

SQL> select * from test; A

--------------------------------------- 1 2

SQL> alter system switch logfile; Statement processed.

SQL> alter system switch logfile; Statement processed.

SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual; TO_CHAR(SYSDATE,'YY ------------------- 2003-05-21 14:43:01 SQL> drop table test; Table dropped.

4、 准备恢复到时间点T1,找回删除的表,先关闭数据库:

SQL> shutdown immediate; Database closed.

Database dismounted.

Oracle instance shut down.

5、 拷贝刚才备份的所有数据文件回来

C:\\>copy D:\\DATABAK\\*.DBF D:\\Oracle\\ORADATA\\TEST\\

6、 启动到mount下

SQL> startup mount;

Oracle instance started.

Total System Global Area 102020364 bytes Fixed Size 70924 bytes Variable Size 85487616 bytes Database Buffers 16384000 bytes Redo Buffers 77824 bytes Database mounted.

7、 开始不完全恢复数据库到T1时间

SQL> recover database until time '2003-05-21:14:43:01';

ORA-00279: change 30944 generated at 05/21/2003 14:40:06 needed for thread 1 ORA-00289: suggestion : D:\\Oracle\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00191.ARC

ORA-00280: change 30944 for thread 1 is in sequence #191

Specify log: {=suggested | filename | AUTO | CANCEL} auto

Log applied.

Media recovery complete.

8、 打开数据库,检查数据

SQL> alter database open resetlogs;

Database altered.

SQL> select * from test; A

--------------------------------------- 1 2

说明:

1、不完全恢复最好备份所有的数据,冷备份亦可,因为恢复过程是从备份点往后恢复的,如果

因为其中一个数据文件的时间戳(SCN)大于要恢复的时间点,那么恢复都是不可能成功的; 2、不完全恢复有三种方式,过程都一样,仅仅是recover命令有所不一样,这里用基于时间

的恢复作为示例;

3、不完全恢复之后,都必须用resetlogs的方式打开数据库,建议马上再做一次全备份,因

为resetlogs之后再用以前的备份恢复是很难了;

4、以上是在删除之前获得时间,但是实际应用中,很难知道删除之前的实际时间,但可以采用

大致时间即可,或可以采用分析日志文件(logmnr),取得精确的需要恢复的时间;

5、一般都是在测试机后备用机器上采用这种不完全恢复,恢复之后导出/导入被误删的表回生

产系统.

4.4.2 RMAN备份下的基于改变的恢复

以上用OS备份说明了一个基于时间的恢复,现在用RMAN说明一个基于改变的恢复

1、 连接数据库,创建测试表并插入记录

SQL> connect internal/password as sysdba; Connected.

SQL> create table test(a int); Table created

SQL> insert into test values(1); 1 row inserted SQL> commit; Commit complete

2、 备份数据库

C:\\>rman

Recovery Manager: Release 8.1.6.0.0 - Production RMAN> connect rcvcat rman/rman@back

RMAN-06008: connected to recovery catalog database RMAN> connect target internal/virpure

RMAN-06005: connected to target database: TEST (DBID=874705288)

RMAN> run{

2> allocate channel c1 type disk;

3> backup full tag 'dbfull' format 'd:\\backup\\full%u_%s_%p' database 4> include current controlfile;

5> sql 'alter system archive log current'; 6> release channel c1; 7> }

//屏幕输出内容冗长,省略--编辑 RMAN>

3、 删除测试表,在删除之前,便于测试,继续插入数据并应用到归档,并获取删除前的scn

号。

SQL> insert into test values(2); 1 row inserted SQL> commit; Commit complete

SQL> select * from test; A

--------------------------------------- 1 2

SQL> alter system switch logfile; Statement processed.

SQL> alter system switch logfile; Statement processed.

SQL> select max(ktuxescnw * power(2, 32) + ktuxescnb) scn from x$ktuxe; SCN

---------- 31014

SQL> drop table test; Table dropped.

4、 准备恢复到SCN 31014,先关闭数据库,然后启动到mount下

SQL> shutdown immediate; Database closed.

Database dismounted.

Oracle instance shut down. SQL> startup mount;

5、 开始恢复到改变点SCN 31014

RMAN> run{

2> allocate channel c1 type disk; 3> restore database;

4> recover database until scn 31014; 5> sql 'ALTER DATABASE OPEN RESETLOGS'; 6> release channel c1; 7> }

RMAN-03022: compiling command: allocate RMAN-03023: executing command: allocate RMAN-08030: allocated channel: c1

RMAN-08500: channel c1: sid=10 devtype=DISK RMAN-03022: compiling command: restore RMAN-03022: compiling command: IRESTORE RMAN-03023: executing command: IRESTORE

RMAN-08016: channel c1: starting datafile backupset restore

RMAN-08502: set_count=1 set_stamp=494613682 creation_time=21-MAY-03

RMAN-08089: channel c1: specifying datafile(s) to restore from backup set RMAN-08523: restoring datafile 00001 to D:\\Oracle\\ORADATA\\TEST\\SYSTEM01.DBF RMAN-08523: restoring datafile 00002 to D:\\Oracle\\ORADATA\\TEST\\RBS01.DBF RMAN-08523: restoring datafile 00003 to D:\\Oracle\\ORADATA\\TEST\\USERS01.DBF RMAN-08523: restoring datafile 00004 to D:\\Oracle\\ORADATA\\TEST\\TEMP01.DBF RMAN-08523: restoring datafile 00005 to D:\\Oracle\\ORADATA\\TEST\\TOOLS01.DBF RMAN-08523: restoring datafile 00006 to D:\\Oracle\\ORADATA\\TEST\\INDX01.DBF RMAN-08023: channel c1: restored backup piece 1

RMAN-08511: piece handle=D:\\BACKUP\\FULL01ENMD5I_1_1 tag=DBFULL params=NULL RMAN-08024: channel c1: restore complete

RMAN-03023: executing command: partial resync

RMAN-08003: starting partial resync of recovery catalog RMAN-08005: partial resync complete RMAN-03022: compiling command: recover RMAN-03022: compiling command: recover(1) RMAN-03022: compiling command: recover(2) RMAN-03022: compiling command: recover(3) RMAN-03023: executing command: recover(3) RMAN-08054: starting media recovery

RMAN-03022: compiling command: recover(4)

RMAN-06050: archivelog thread 1 sequence 191 is already on disk as file D:\\ORACL E\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00191.ARC

RMAN-06050: archivelog thread 1 sequence 192 is already on disk as file D:\\ORACL E\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00192.ARC RMAN-03023: executing command: recover(4) RMAN-08515: archivelog filename=D:\\Oracle\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00191.AR C thread=1 sequence=191 RMAN-08515:archivelog

filename=D:\\Oracle\\ORADATA\\TEST\\ARCHIVE\\TESTT001S00192.ARC Thread=1 sequence=192

RMAN-08055: media recovery complete RMAN-03022: compiling command: sql

RMAN-06162: sql statement: ALTER DATABASE OPEN RESETLOGS RMAN-03023: executing command: sql

RMAN-03022: compiling command: release RMAN-03023: executing command: release RMAN-08031: released channel: c1

6、 检查数据

Database altered.

SQL> select * from test; A

--------------------------------------- 1 2 可以看到,表依然存在。

说明:

1、 RMAN也可以实现不完全恢复,方法比OS备份恢复的方法更简单可靠;

2、 RMAN可以基于时间,基于改变与基于日志序列的不完全恢复,基于日志序列的恢复可以指

定恢复到哪个日志序列,如 run {

allocate channel ch1 type disk;

allocate channel ch2 type 'sbt_tape'; set until logseq 1234 thread 1;

restore controlfile to '$Oracle_HOME/dbs/cf1.f' ; replicate controlfile from '$Oracle_HOME/dbs/cf1.f'; alter database mount; restore database; recover database;

sql \

}

3、 与所有的不完全恢复一样,必须在mount下,restore所有备份数据文件,需要

resetlogs;

4、 基于改变的恢复比基于时间的恢复更可靠,但是可能也更复杂,需要知道需要恢复到哪一

个改变号(SCN),在正常生产中,获取SCN的办法其实也有很多,如查询数据库字典表(V$archived_log or v$log_history),或分析归档与联机日志(logmnr)等。

第五章 其它恢复案例

5.1 损坏联机日志的恢复方法


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