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

总结

任何时候数据库的还原和恢复因环境和错误的不一而不同,认真有效的阅读文档,理解工作原理,然后在加上重复的实验方能起到良好的效果,实验本身是动手实践的步骤,但同时也是理论实践结合的强有效方式。
--The end(2015-05-30)