Oracle RMAN物理备份技术详解 - 技术频道

多个通道执行交叉验证和删除备份

在执行CROSSCHECK和DELETE之前可以配置或者手工分配多个通道，RMAN将搜索和删除在不同类型的设备上执行的备份文件。适用以下情况：

1、用一个命令交叉验证或者删除在不同设备上备份的文件(例如磁带和磁盘上都有备份文件)。

2、交叉验证或者删除工作在RAC环境下备份到每个节点上的备份文件。

RMAN如何在多通道下执行CROSSCHECK和DELETE：

举个例子，我们的备份文件全部在磁盘上，磁带上没有备份文件，而我们给出了如下备份脚本，那么RMAN将会执行前边的两个磁盘CROSSCHECK而不会执行第三条磁带CROSSCHECK。

RUN
...{ALLOCATE CHANNEL FOR MAINTENANCE DEVICE TYPE DISK CONNECT 'SYS/oracle@node1';
AlLOCATE CHANNEL FOR MAINTENANCE DEVICE TYPE DISK CONNECT 'SYS/oracle@node2';
ALLOCATE CHANNEL FOR MAINTENANCE DEVICE TYPE sbt;
CROSSCHECK BACKUP OF DATABASE;
}

注意：如果RMAN标记为EXPIRED状态的备份文件被修复后，我们执行DELETE EXPIRED BACKUP；命令后将会收到如下提示：

RMAN> delete expired backup;

使用通道 ORA_DISK_1

备份段列表
BP 关键字  BS 关键字  Pc# Cp# 状态      设备类型段名称
------- ------- --- --- ----------- ----------- ----------
112     117     1   1   EXPIRED     DISK        D:\ORACLE\PRODUCT\10.2.0\FLASH_R
ECOVERY_AREA\ROME\BACKUPSET\2007_02_05\O1_MF_NNNDF_TAG20070205T113315_2WF9CYG5_.
BKP

是否确定要删除以上对象 (输入 YES 或 NO)? yes

RMAN-06207: 警告: 由于状态不匹配, 所以不能删除 1 对象 (对于 DISK 通道)。
RMAN-06208: 请用 CROSSCHECK 命令修正状态
RMAN-06210: 不匹配对象的列表
RMAN-06211: ==========================
RMAN-06212: 对象类型   文件名/句柄
RMAN-06213: --------------- ---------------------------------------------------
RMAN-06214: Backup Piece    D:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\ROME\BA
CKUPSET\2007_02_05\O1_MF_NNNDF_TAG20070205T113315_2WF9CYG5_.BKP

一个命令交叉验证磁盘和磁带备份的例子：

CONFIGURE DEVICE TYPE sbt PARALLELISM 1;
CONFIGURE DEFAULT DEVICE TYPE to sbt;
CROSSCHECK BACKUP OF DATABASE;

示例输出文件如下：

allocated channel: ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: sid=12 devtype=SBT_TAPE
channel ORA_SBT_TAPE_1: WARNING: Oracle Test Disk API
using channel ORA_DISK_1
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/oracle/dbs/16c5esv4_1_1 recid=36 stamp=408384484
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=/oracle/dbs/c-674966176-20000915-01 recid=37 stamp=408384496
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=12c5erb2_1_1 recid=32 stamp=408382820
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=13c5erba_1_1 recid=33 stamp=408382829
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=14c5erce_1_1 recid=34 stamp=408382863
crosschecked backup piece: found to be 'AVAILABLE'
backup piece handle=c-674966176-20000915-00 recid=35 stamp=408382869

如果没有配置磁带备份设备，也可以手工执行分配通道：

ALLOCATE CHANNEL FOR MAINTENANCE DEVICE TYPE sbt;
CROSSCHECK BACKUP OF DATABASE;

RAC环境下交叉验证的例子：

CONFIGURE DEVICE TYPE DISK PARALLELISM 2;
CONFIGURE CHANNEL 1 DEVICE TYPE DISK CONNECT 'SYS/oracle@node_1';
CONFIGURE CHANNEL 2 DEVICE TYPE DISK CONNECT 'SYS/oracle@node_2';
CROSSCHECK BACKUP;

一个删除磁带和磁盘备份的例子：

CONFIGURE DEVICE TYPE sbt PARALLELISM 1;
CONFIGURE DEFAULT DEVICE TYPE TO sbt;
DELETE BACKUPSET;

示例输出文件如下：

using channel ORA_SBT_TAPE_1
using channel ORA_DISK_1

List of Backup Pieces
BP Key  BS Key  Pc# Cp# Status      Device Type Piece Name
------- ------- --- --- ----------- ----------- ----------
388     387     1   1   AVAILABLE   SBT_TAPE    12c5erb2_1_1
397     396     1   1   UNAVAILABLE SBT_TAPE    13c5erba_1_1
424     423     1   1   AVAILABLE   SBT_TAPE    14c5erce_1_1
428     427     1   1   AVAILABLE   SBT_TAPE    c-674966176-20000915-00
433     432     1   1   AVAILABLE   DISK        /oracle/dbs/16c5esv4_1_1
437     436     1   1   AVAILABLE   DISK     /oracle/dbs/c-674966176-20000915-01

Do you really want to delete the above objects (enter YES or NO)? y
deleted backup piece
backup piece handle=/oracle/dbs/16c5esv4_1_1 recid=36 stamp=408384484
deleted backup piece
backup piece handle=/oracle/dbs/c-674966176-20000915-01 recid=37 stamp=408384496
deleted backup piece
backup piece handle=12c5erb2_1_1 recid=32 stamp=408382820
deleted backup piece
backup piece handle=13c5erba_1_1 recid=33 stamp=408382829
deleted backup piece
backup piece handle=14c5erce_1_1 recid=34 stamp=408382863
deleted backup piece
backup piece handle=c-674966176-20000915-00 recid=35 stamp=408382869

释放多个通道,如下命令可以释放所有通道：

RELEASE CHANNEL;

使用RMAN删除数据库

RMAN连接到处于MOUNT状态的TARGET数据库，就可以删除TARGET数据库，而不需要连接恢复目录；如果RMAN同时连接到恢复目录，并且指定INCLUDE COPIES AND BACKUPS参数，RMAN将删除恢复目录中的备份记录。

生成备份文件目录：

RMAN>catalog start with 'd:\oracle\product\10.2.0\flash_recovery_area';
RMAN> DELETE BACKUPSET; # deletes all backups
RMAN> DELETE COPY; # delete all image copies (including archived logs)
RMAN> DROP DATABASE; # delete all database files and unregister the database

修改备份记录的状态：

CHANGE DATAFILECOPY '/tmp/control01.ctl' UNAVAILABLE;
CHANGE COPY OF ARCHIVELOG SEQUENCE BETWEEN 1000 AND 1012 UNAVAILABLE;
CHANGE BACKUPSET 12 UNAVAILABLE;
CHANGE BACKUP OF SPFILE TAG "TAG20020208T154556" UNAVAILABLE;
CHANGE DATAFILECOPY '/tmp/system01.dbf' AVAILABLE;
CHANGE BACKUPSET 12 AVAILABLE;
CHANGE BACKUP OF SPFILE TAG "TAG20020208T154556" AVAILABLE;

修改备份记录状态使得保留冗余策略外的备份不被删除。

我们可以在执行备份的时候直接指定BACKUP...KEEP来把备份文件标记为长期备份。有一点需要注意，如果使用恢复目录来存储备份记录的话，我们应该执行BACKUP...KEEP FOREVER。

我们也可以用CHANGE命令来把一个备份标记为长期备份：

CHANGE BACKUPSET 231 KEEP;
CHANGE BACKUPSET 231 NOKEEP;
CHANGE DATAFILECOPY '/tmp/system01.dbf' KEEP UNTIL 'SYSDATE+180';