浅一下oracle热备份users表空间

Posted 2020-08-11

数据库要运行在归档模式下:
archive log list
shutdown immediate
startup mount
alter database archivelog;
alter database open;
archive log list

热备份users表空间：

(1)实验环境相关信息查看

创建备份路径

mkdir -p /home/oracle/hotbk/

这里为了测试更改归档文件的路径

mkdir /home/oracle/arc_orcl_dest1/
alter system set log_archive_dest_1=‘location=/home/oracle/arc_orcl_dest1/‘;
select sequence#,name from v$archived_log;
alter system switch logfile;
alter system switch logfile;
alter system switch logfile;
select sequence#,name from v$archived_log;

查看数据文件

SQL> select name from v$datafile;
NAME
----------------------------------------------------------------------------------------------------
/u01/app/oracle/oradata/orcl/system01.dbf
/u01/app/oracle/oradata/orcl/sysaux01.dbf
/u01/app/oracle/oradata/orcl/undotbs01.dbf
/u01/app/oracle/oradata/orcl/users01.dbf
Elapsed: 00:00:00.00

查看表空间

SQL> select name from v$tablespace;
NAME
------------------------------
SYSTEM
SYSAUX
UNDOTBS1
USERS
TEMP
Elapsed: 00:00:00.00

查看备份信息

SQL> select * from v$backup;
     FILE# STATUS         CHANGE# TIME
---------- ------------------ ---------- ---------
     1 NOT ACTIVE               0
     2 NOT ACTIVE               0
     3 NOT ACTIVE               0
     4 NOT ACTIVE         1027726 27-SEP-16
Elapsed: 00:00:00.00

SQL> select name,file# from v$datafile
  2  ;
NAME
----------------------------------------------------------------------------------------------------
     FILE#
----------
/u01/app/oracle/oradata/orcl/system01.dbf
     1
/u01/app/oracle/oradata/orcl/sysaux01.dbf
     2
/u01/app/oracle/oradata/orcl/undotbs01.dbf
     3
/u01/app/oracle/oradata/orcl/users01.dbf
     4
Elapsed: 00:00:00.00

查看文件号及其检查点的编号

SQL>  select file#,checkpoint_change# from v$datafile;
     FILE# CHECKPOINT_CHANGE#
---------- ------------------
     1          1027476
     2          1027476
     3          1027476
     4          1027726
Elapsed: 00:00:00.01

SQL>  select file#,checkpoint_change# from v$datafile_header;
     FILE# CHECKPOINT_CHANGE#
---------- ------------------
     1          1027476
     2          1027476
     3          1027476
     4          1027726
Elapsed: 00:00:00.01

(2)真正开始备份
这里备份users这个表空间。

alter tablespace users begin backup;
!cp -v /u01/app/oracle/oradata/orcl/users01.dbf /home/oracle/hotbk/
alter tablespace users end backup;

查看备份点

SQL> select * from v$backup;
     FILE# STATUS         CHANGE# TIME
---------- ------------------ ---------- ---------
     1 NOT ACTIVE               0
     2 NOT ACTIVE               0
     3 NOT ACTIVE               0
     4 NOT ACTIVE         1028454 27-SEP-16
Elapsed: 00:00:00.00

(3)模拟数据修改
SQL> select owner,table_name from dba_tables where tablespace_name=‘USERS‘;
create table scott.ob2 as select * from dba_objects;
select count(*) from scott.ob2;
commit;
alter system switch logfile;
查看数据变化情况

SQL> select file#,checkpoint_change# from v$datafile;
     FILE# CHECKPOINT_CHANGE#
---------- ------------------
     1          1028188
     2          1028188
     3          1028188
     4          1028454
Elapsed: 00:00:00.00
SQL>  select file#,checkpoint_change# from v$datafile_header;
     FILE# CHECKPOINT_CHANGE#
---------- ------------------
     1          1028188
     2          1028188
     3          1028188
     4          1028454
Elapsed: 00:00:00.00

和之前的比较，发现checkpoint_change发生了变化。

查看有没有修复的数据块：

SQL> select * from v$recover_file;
no rows selected
Elapsed: 00:00:00.00

模拟数据文件损坏

SQL> !rm -f /u01/app/oracle/oradata/orcl/users01.dbf

###### alter system flush buffer_cache;这里不要执行
## startup force

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 4041949184 bytes
Fixed Size            2259520 bytes
Variable Size          889193920 bytes
Database Buffers     3137339392 bytes
Redo Buffers           13156352 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 4 - see DBWR trace file
ORA-01110: data file 4: ‘/u01/app/oracle/oradata/orcl/users01.dbf‘

select * from v$recover_file;

SQL> select * from v$recover_file;
     FILE# ONLINE  ONLINE_ ERROR
---------- ------- ------- -----------------------------------------------------------------
   CHANGE# TIME
---------- ---------
     4 ONLINE  ONLINE  FILE NOT FOUND
     0
Elapsed: 00:00:00.01

备注：这里4号文件找不到


还原：使用备份的文件代替丢失的文件

cp /home/oracle/hotbk/users01.dbf /u01/app/oracle/oradata/orcl/users01.dbf

再查看一下情况：
SQL> select * from v$recover_file;

     FILE# ONLINE  ONLINE_ ERROR
---------- ------- ------- -----------------------------------------------------------------
   CHANGE# TIME
---------- ---------
     4 ONLINE  ONLINE
   1028454 27-SEP-16
报ERROR错误

恢复：使用备份之后的日志对数据文件进行前滚（把数据修改重现）

recover datafile 4;

SQL> recover datafile 4;
Media recovery complete.
SQL> select * from v$recover_file;

no rows selected

Elapsed: 00:00:00.00

SQL> alter database open;

Database altered.

Elapsed: 00:00:01.43
SQL> select count(*) from scott.ob2;

  COUNT(*)
----------
     86344

Elapsed: 00:00:00.02

到这里已经搞定了！！！！

写得不好，如果有什么错误请指出，谢谢！！！！

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