rman的使用练习

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rman target /

或者

rman target sys/passwd@dbname

全量备份

oracle必须处于归档模式才可以进行全量备份

sqlplus / as sysdba << EOF
SELECT log_mode FROM v\$database;
EOF

如果结果是

SQL>
LOG_MODE
------------
ARCHIVELOG

则可以执行全量备份

在rman中执行

RMAN> backup database plus archivelog;

来备份所有数据文件和归档文件

如果不指定位置，oracle会将备份文件保存至默认路径，我们可以使用format指定位置

backup database format '/opt/oracle_backup/data_backup/20250329_data.dbf' plus archivelog format '/opt/oracle_backup/arch_backup/20250329_arch.dbf' ;

使用 backup database命令则只备份数据文件

恢复数据

备份完成后可以使用 list backup 命令来查看备份情况，每份备份都有tag
恢复时可以指定tag

RMAN> restore database from tag='TAG20250327T172855'

恢复数据使用restore database和recover database，需要启动到mount状态

RMAN> restore database;

Starting restore at 27-MAR-25
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=6 device type=DISK

skipping datafile 1; already restored to file /opt/app/oracle/oradata/ORCL/system01.dbf
skipping datafile 2; already restored to file /opt/app/oracle/oradata/ORCL/sysaux01.dbf
skipping datafile 3; already restored to file /opt/app/oracle/oradata/ORCL/undotbs01.dbf
skipping datafile 4; already restored to file /opt/app/oracle/oradata/ORCL/users01.dbf
skipping datafile 5; already restored to file /opt/app/oracle/oradata/ORCL/orclys2.dbf
skipping datafile 6; already restored to file /opt/app/oracle/oradata/ORCL/orclys1.dbf
skipping datafile 7; already restored to file /opt/app/oracle/oradata/ORCL/TEST_2.dbf
skipping datafile 8; already restored to file /opt/app/oracle/oradata/ORCL/ORCL/datafile/o1_mf_autoys_mwx9j8kb_.dbf
skipping datafile 9; already restored to file /opt/app/oracle/product/19.3.0/dbhome_1/dbs/SMALL.dbf
restore not done; all files read only, offline, excluded, or already restored
Finished restore at 27-MAR-25

RMAN> recover database;

Starting recover at 27-MAR-25
using channel ORA_DISK_1

starting media recovery
media recovery complete, elapsed time: 00:00:02

Finished recover at 27-MAR-25

报错处理

在使用同一个命令测试rman备份时报错文件已存在，但是确实将文件删过了

backup database format '/opt/oracle_backup/data_backup/20250329_data.dbf' plus archivelog format '/opt/oracle_backup/arch_backup/20250329_arch.dbf' ;

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup plus archivelog command at 03/27/2025 17:15:18
ORA-19504: failed to create file "/opt/oracle_backup/arch_backup/20250329_arch1.dbf"
ORA-27038: created file already exists
Additional information: 1

问过AI后得知，文件名不能重复，如果用一个文件名备份过了，就算删除了文件，记录也还在，就会报错
解决办法是给文件名加上%U，这个参数会生成唯一ID，就不会重复了

RMAN> backup database format '/opt/oracle_backup/data_backup/20250329_data_%U.dbf' plus archivelog format '/opt/oracle_backup/arch_backup/20250329_arch_%U.dbf';

增量备份

增量备份分为全量备份、累计增量和差异增量

零级备份

backup incremental level 0 database;

一级差异增量

backup incremental level 1 database;

一级累计增量

backup incremental level 1 cumulative database;

恢复语法和普通恢复一样