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数据库灾难性环境下恢复

所谓灾难性是指磁盘故障或其它原因导致数据库相关的文件全部丢失或损坏无法进行修复,必须通过备份进行还原恢复;以下实验模拟丢失所有数据库文件,然后通过备份进行还原恢复。

版本和数据库文件信息

Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production PL/SQL Release 11.2.0.3.0 - Production CORE    11.2.0.3.0      Production TNS for Linux: Version 11.2.0.3.0 - Production NLSRTL Version 11.2.0.3.0 - Production SQL> column name format a50 SQL> select file#,status,name from v$datafile;     FILE# STATUS  NAME ---------- ------- --------------------------------------------------  1 SYSTEM  /u01/oradata/sydb/system01.dbf  2 ONLINE  /u01/oradata/sydb/sysaux01.dbf  3 ONLINE  /u01/oradata/sydb/undotbs01.dbf  4 ONLINE  /u01/oradata/sydb/users01.dbf  5 ONLINE  /u01/oradata/sydb/tbs01.dbf SQL> column member format a50 SQL> select * from v$Logfile;     GROUP# STATUS  TYPE    MEMBER     IS_ ---------- ------- ------- -------------------------------------------------- ---  1 ONLINE  /u01/oradata/sydb/REDO01.LOG       NO  2 ONLINE  /u01/oradata/sydb/REDO02.LOG       NO SQL> select * from v$controlfile; STATUS  NAME       IS_ BLOCK_SIZE FILE_SIZE_BLKS ------- -------------------------------------------------- --- ---------- --------------         /u01/oradata/sydb/control01.ctl    NO       16384    668

备份数据库

注意:备份数据库时如果配置了 configure exclude for tablespace tbsname 的表空间是不会进行备份的,恢复表空间备份configure exclude for tablespace tbsname clear;如果没有设置自动备份控制文件和参数文件,要在备份脚本最后手动添加备份控制文件脚本;设置自动备份控制文件和参数文件:

 CONFIGURE CONTROLFILE AUTOBACKUP On;  CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/u01/backup/%F_%d_controlfile.bkp';

控制文件名格式必须包含%F,%F的格式为:c-IIIIIIIIII-YYYYMMDD-QQ,IIIIIIIIII(10位)代表DBID发生灾难时可以通过它知道数据库ID,YYYYMMDD代表自动备份时的timestamp,QQ代表是十六进制的序列号,起始值为:00,最大值为:FF。开始备份数据

 run  {  allocate channel dev type disk;  allocate channel dev2 type disk;  backup incremental level 0 database plus archivelog delete input  tag 'sydb_incr_level0'  format '/u01/backup/%d_%s_%U';  release channel dev;  release channel dev2;  }  allocated channel: dev channel dev: SID=181 device type=DISK  allocated channel: dev2 channel dev2: SID=18 device type=DISK   Starting backup at 29-MAY-15 current log archived channel dev: starting archived log backup set channel dev: specifying archived log(s) in backup set input archived log thread=1 sequence=17 RECID=1 STAMP=880994007 channel dev: starting piece 1 at 29-MAY-15 channel dev2: starting archived log backup set channel dev2: specifying archived log(s) in backup set input archived log thread=1 sequence=18 RECID=2 STAMP=880994016 input archived log thread=1 sequence=19 RECID=3 STAMP=880994311 channel dev2: starting piece 1 at 29-MAY-15 channel dev: finished piece 1 at 29-MAY-15 piece handle=/u01/backup/SYDB_1_01q85q07_1_1 tag=SYDB_INCR_LEVEL0 comment=NONE channel dev: backup set complete, elapsed time: 00:00:07 channel dev: deleting archived log(s) archived log file name=/u01/app/product/11.2.3/db_1/dbs/arch1_17_880905808.dbf RECID=1 STAMP=880994007 channel dev2: finished piece 1 at 29-MAY-15 piece handle=/u01/backup/SYDB_2_02q85q07_1_1 tag=SYDB_INCR_LEVEL0 comment=NONE channel dev2: backup set complete, elapsed time: 00:00:08 channel dev2: deleting archived log(s) archived log file name=/u01/app/product/11.2.3/db_1/dbs/arch1_18_880905808.dbf RECID=2 STAMP=880994016 archived log file name=/u01/app/product/11.2.3/db_1/dbs/arch1_19_880905808.dbf RECID=3 STAMP=880994311 Finished backup at 29-MAY-15  Starting backup at 29-MAY-15 channel dev: starting incremental level 0 datafile backup set channel dev: specifying datafile(s) in backup set input datafile file number=00001 name=/u01/oradata/sydb/system01.dbf input datafile file number=00004 name=/u01/oradata/sydb/users01.dbf input datafile file number=00005 name=/u01/oradata/sydb/tbs01.dbf channel dev: starting piece 1 at 29-MAY-15 channel dev2: starting incremental level 0 datafile backup set channel dev2: specifying datafile(s) in backup set input datafile file number=00003 name=/u01/oradata/sydb/undotbs01.dbf input datafile file number=00002 name=/u01/oradata/sydb/sysaux01.dbf channel dev2: starting piece 1 at 29-MAY-15 channel dev: finished piece 1 at 29-MAY-15 piece handle=/u01/app/product/11.2.3/db_1/dbs/03q85q0f_1_1 tag=TAG20150529T163839 comment=NONE channel dev: backup set complete, elapsed time: 00:00:35 channel dev2: finished piece 1 at 29-MAY-15 piece handle=/u01/app/product/11.2.3/db_1/dbs/04q85q0f_1_1 tag=TAG20150529T163839 comment=NONE channel dev2: backup set complete, elapsed time: 00:00:35 Finished backup at 29-MAY-15  Starting backup at 29-MAY-15 current log archived channel dev: starting archived log backup set channel dev: specifying archived log(s) in backup set input archived log thread=1 sequence=20 RECID=4 STAMP=880994354 channel dev: starting piece 1 at 29-MAY-15 channel dev: finished piece 1 at 29-MAY-15 piece handle=/u01/backup/SYDB_5_05q85q1i_1_1 tag=SYDB_INCR_LEVEL0 comment=NONE channel dev: backup set complete, elapsed time: 00:00:01 channel dev: deleting archived log(s) archived log file name=/u01/app/product/11.2.3/db_1/dbs/arch1_20_880905808.dbf RECID=4 STAMP=880994354 Finished backup at 29-MAY-15  Starting Control File and SPFILE Autobackup at 29-MAY-15 piece handle=/u01/backup/c-3634177744-20150529-00_control.bkp comment=NONE Finished Control File and SPFILE Autobackup at 29-MAY-15  released channel: dev  released channel: dev2

通过备份日志可以知道哪些数据文件被备份,哪些没有被备份或没有备份成功,比如:发现较多数据块损坏、表空间被排除备份(exclude)、表空间被skip;关注这些信息非常重要,因为一旦灾难发生,它意味着你的数据库恢复成功率,也有助于对备份脚本的优化和调整。

验证数据库可恢复性

验证可恢复性可以发现一些忽略的问题,及时处理;

RMAN> restore database validate;  Starting restore at 29-MAY-15 allocated channel: ORA_DISK_1 channel ORA_DISK_1: SID=181 device type=DISK  channel ORA_DISK_1: starting validation of datafile backup set channel ORA_DISK_1: reading from backup piece /u01/app/product/11.2.3/db_1/dbs/03q85q0f_1_1 channel ORA_DISK_1: piece handle=/u01/app/product/11.2.3/db_1/dbs/03q85q0f_1_1 tag=TAG20150529T163839 channel ORA_DISK_1: restored backup piece 1 channel ORA_DISK_1: validation complete, elapsed time: 00:00:03 channel ORA_DISK_1: starting validation of datafile backup set channel ORA_DISK_1: reading from backup piece /u01/app/product/11.2.3/db_1/dbs/04q85q0f_1_1 channel ORA_DISK_1: piece handle=/u01/app/product/11.2.3/db_1/dbs/04q85q0f_1_1 tag=TAG20150529T163839 channel ORA_DISK_1: restored backup piece 1 channel ORA_DISK_1: validation complete, elapsed time: 00:00:01 Finished restore at 29-MAY-15

删除数据库相关文件模拟灾难

rm /u01/oradata/sydb/system01.dbf rm /u01/oradata/sydb/sysaux01.dbf rm /u01/oradata/sydb/undotbs01.dbf rm /u01/oradata/sydb/tbs01.dbf rm /u01/oradata/sydb/control01.ctl rm /u01/oradata/sydb/REDO01.LOG  rm /u01/oradata/sydb/REDO02.LOG  rm /u01/app/product/11.2.3/db_1/dbs/spfilesydb.ora

数据库恢复

恢复参数文件和控制文件

数据库启动时会先查找spfile,然后在找spfile.ora,再找文件initpfile,如果这些文件都没有找到报错并停止启动;so 先创建一个基本的init pfile;

$ vim /u01/app/product/11.2.3/db_1/dbs/initsydb.ora db_name='sydb' memory_target=200m control_files='/u01/oradata/sydb/control01.ctl' db_block_size=32768

如果你的数据块大小为非8kb,你又想在恢复控制文件后完成其它操作,如mount控制文件,则你必须在init 文件中指定数据块大小;

SQL> startup nomount ORACLE instance started.  Total System Global Area  208769024 bytes Fixed Size                  2226936 bytes Variable Size             109053192 bytes Database Buffers           92274688 bytes Redo Buffers                5214208 bytes  $ rman target / RMAN> restore spfile from '/u01/backup/c-3634177744-20150529-00_control.bkp';  Starting restore at 29-MAY-15 using channel ORA_DISK_1  channel ORA_DISK_1: restoring spfile from AUTOBACKUP /u01/backup/c-3634177744-20150529-00_control.bkp channel ORA_DISK_1: SPFILE restore from AUTOBACKUP complete Finished restore at 29-MAY-15  RMAN> restore controlfile from '/u01/backup/c-3634177744-20150529-00_control.bkp';  Starting restore at 29-MAY-15 using channel ORA_DISK_1  channel ORA_DISK_1: restoring control file channel ORA_DISK_1: restore complete, elapsed time: 00:00:01 output file name=/u01/oradata/sydb/control01.ctl Finished restore at 29-MAY-15 RMAN> alter database mount;  database mounted released channel: ORA_DISK_1

查看备份文件和确定可恢复的最大归档日志序列

注:如果目录名发生改变或文件发生位置移动,先使用 catalog start with '/dir' 将文件catalog;

RMAN> list backup of database; List of Backup Sets =================== BS Key  Type LV Size       Device Type Elapsed Time Completion Time ------- ---- -- ---------- ----------- ------------ --------------- 3       Incr 0  180.53M    DISK 00:00:29     29-MAY-15        BP Key: 3   Status: AVAILABLE  Compressed: NO  Tag: TAG20150529T163839  Piece Name: /u01/app/product/11.2.3/db_1/dbs/04q85q0f_1_1   List of Datafiles in backup set 3   File LV Type Ckp SCN    Ckp Time  Name   ---- -- ---- ---------- --------- ----   2    0  Incr 436655     29-MAY-15 /u01/oradata/sydb/sysaux01.dbf   3    0  Incr 436655     29-MAY-15 /u01/oradata/sydb/undotbs01.dbf BS Key  Type LV Size       Device Type Elapsed Time Completion Time ------- ---- -- ---------- ----------- ------------ --------------- 4       Incr 0  380.94M    DISK 00:00:29     29-MAY-15        BP Key: 4   Status: AVAILABLE  Compressed: NO  Tag: TAG20150529T163839  Piece Name: /u01/app/product/11.2.3/db_1/dbs/03q85q0f_1_1   List of Datafiles in backup set 4   File LV Type Ckp SCN    Ckp Time  Name   ---- -- ---- ---------- --------- ----   1    0  Incr 436654     29-MAY-15 /u01/oradata/sydb/system01.dbf   4    0  Incr 436654     29-MAY-15 /u01/oradata/sydb/users01.dbf   5    0  Incr 436654     29-MAY-15 /u01/oradata/sydb/tbs01.dbf RMAN> list backup of archivelog all; List of Backup Sets =================== BS Key  Size       Device Type Elapsed Time Completion Time ------- ---------- ----------- ------------ --------------- 1       45.49M     DISK 00:00:04     29-MAY-15        BP Key: 1   Status: AVAILABLE  Compressed: NO  Tag: SYDB_INCR_LEVEL0  Piece Name: /u01/backup/SYDB_1_01q85q07_1_1   List of Archived Logs in backup set 1   Thrd Seq     Low SCN    Low Time  Next SCN   Next Time   ---- ------- ---------- --------- ---------- ---------   1    17      427739     29-MAY-15 436110     29-MAY-15 BS Key  Size       Device Type Elapsed Time Completion Time ------- ---------- ----------- ------------ --------------- 2       43.37M     DISK 00:00:04     29-MAY-15        BP Key: 2   Status: AVAILABLE  Compressed: NO  Tag: SYDB_INCR_LEVEL0  Piece Name: /u01/backup/SYDB_2_02q85q07_1_1   List of Archived Logs in backup set 2   Thrd Seq     Low SCN    Low Time  Next SCN   Next Time   ---- ------- ---------- --------- ---------- ---------   1    18      436110     29-MAY-15 436484     29-MAY-15   1    19      436484     29-MAY-15 436643     29-MAY-15 BS Key  Size       Device Type Elapsed Time Completion Time ------- ---------- ----------- ------------ --------------- 5       90.00K     DISK 00:00:00     29-MAY-15        BP Key: 5   Status: AVAILABLE  Compressed: NO  Tag: SYDB_INCR_LEVEL0  Piece Name: /u01/backup/SYDB_5_05q85q1i_1_1   List of Archived Logs in backup set 5   Thrd Seq     Low SCN    Low Time  Next SCN   Next Time   ---- ------- ---------- --------- ---------- ---------   1    20      436643     29-MAY-15 436756     29-MAY-15

从上面的信息中可以看出最大可恢复到的日志序列为20,恢复时设置until sequence 21,数据库即可应用所有的归档日志;

RMAN> restore database until sequence 21;  Starting restore at 29-MAY-15 using channel ORA_DISK_1  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 00001 to /u01/oradata/sydb/system01.dbf channel ORA_DISK_1: restoring datafile 00004 to /u01/oradata/sydb/users01.dbf channel ORA_DISK_1: restoring datafile 00005 to /u01/oradata/sydb/tbs01.dbf channel ORA_DISK_1: reading from backup piece /u01/app/product/11.2.3/db_1/dbs/03q85q0f_1_1 channel ORA_DISK_1: piece handle=/u01/app/product/11.2.3/db_1/dbs/03q85q0f_1_1 tag=TAG20150529T163839 channel ORA_DISK_1: restored backup piece 1 channel ORA_DISK_1: restore complete, elapsed time: 00:00:25 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 00002 to /u01/oradata/sydb/sysaux01.dbf channel ORA_DISK_1: restoring datafile 00003 to /u01/oradata/sydb/undotbs01.dbf channel ORA_DISK_1: reading from backup piece /u01/app/product/11.2.3/db_1/dbs/04q85q0f_1_1 channel ORA_DISK_1: piece handle=/u01/app/product/11.2.3/db_1/dbs/04q85q0f_1_1 tag=TAG20150529T163839 channel ORA_DISK_1: restored backup piece 1 channel ORA_DISK_1: restore complete, elapsed time: 00:00:35 Finished restore at 29-MAY-15  RMAN> recover database until sequence 21;  Starting recover at 29-MAY-15 using channel ORA_DISK_1  starting media recovery  channel ORA_DISK_1: starting archived log restore to default destination channel ORA_DISK_1: restoring archived log archived log thread=1 sequence=20 channel ORA_DISK_1: reading from backup piece /u01/backup/SYDB_5_05q85q1i_1_1 channel ORA_DISK_1: piece handle=/u01/backup/SYDB_5_05q85q1i_1_1 tag=SYDB_INCR_LEVEL0 channel ORA_DISK_1: restored backup piece 1 channel ORA_DISK_1: restore complete, elapsed time: 00:00:01 archived log file name=/u01/app/product/11.2.3/db_1/dbs/arch1_20_880905808.dbf thread=1 sequence=20 media recovery complete, elapsed time: 00:00:01 Finished recover at 29-MAY-15

使用resetlogs 方式打开数据库

SYS@sydb>select file#,d.name as "FILE_NAME",t.name as "TABLESPACE_NAME",status,enabled,checkpoint_change#,checkpoint_time,(bytes/1024/1024)"BYTES_MB",blocks,   2  (create_bytes/1024/1024)create_bytes_mb,block_size     3  from v$datafile d left join v$tablespace t   4  on d.ts#=t.ts#;  FILE#   FILE_NAME TABLESPACE_NAME    STATUS  ENABLED  CHECKPOINT_CHANGE# CHECKPOIN  BYTES_MB  BLOCKS CREATE_BYTES_MB BLOCK_SIZE ------------------------------ ------- ---------- ------------------ --------- ---------- ---------- --------------- ---------- 1  /u01/oradata/sydb/system01.dbf  SYSTEM    SYSTEM  READ WRITE  436756      29-MAY-15   400.8125  12826   100     32768 2  /u01/oradata/sydb/sysaux01.dbf  SYSAUX    ONLINE  READ WRITE 436756       29-MAY-15   227.6875 7286     100     32768 3  /u01/oradata/sydb/undotbs01.dbf UNDOTBS01  ONLINE  READ WRITE 436756      29-MAY-15   310       9920    100    32768 4  /u01/oradata/sydb/users01.dbf    USERS     ONLINE  READ WRITE 436756      29-MAY-15   100       3200    100     32768 5  /u01/oradata/sydb/tbs01.dbf     TBS01      ONLINE  READ WRITE 436756      29-MAY-15   98       3136     10     32768  Elapsed: 00:00:00.02 SYS@sydb>alter database open resetlogs;  Database altered.  Elapsed: 00:00:07.41