Oracle linux下 rm 数据文件恢复测试详解

Oracle下rm 删除数据文件恢复

下面是整个测试步骤

1.在数据库open的时候，直接删除test表空间中的数据文件
Last login: Tue Feb  7 10:24:27 2017 from 192.168.36.103
[root@oracle1 ~]# su - oracle
ocrl:/home/oracle@oracle1>ps -ef |grep pmon
oracle    6098     1  0 Feb07 ?        00:00:05 ora_pmon_ocrl
oracle   18634 18603  0 11:34 pts/1    00:00:00 grep pmon
ocrl:/home/oracle@oracle1>sqlplus  /  as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Fri Feb 10 11:36:15 2017

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL> select name from v$datafile;

NAME
--------------------------------------------------------------------------------
/data/oradata/ocrl/datafile/system01.dbf
/data/oradata/ocrl/datafile/sysaux01.dbf
/data/oradata/ocrl/datafile/undotbs01.dbf
/data/oradata/ocrl/datafile/users01.dbf
/data/oradata/ocrl/datafile/test.dbf

SQL> exit
Disconnected from Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options
ocrl:/home/oracle@oracle1>cd /data/oradata/ocrl/datafile/
ocrl:/data/oradata/ocrl/datafile@oracle1>ls
sysaux01.dbf  system01.dbf  test.dbf  undotbs01.dbf  users01.dbf
ocrl:/data/oradata/ocrl/datafile@oracle1>rm -rf test.dbf
ocrl:/data/oradata/ocrl/datafile@oracle1>ls
sysaux01.dbf  system01.dbf  undotbs01.dbf  users01.dbf
ocrl:/data/oradata/ocrl/datafile@oracle1>sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Fri Feb 10 11:37:23 2017

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options
2.尝试在tets表中间中创建表，开始报错
SQL> create table t tablespace test as select * from dual;
create table t tablespace test as select * from dual
                                                *
ERROR at line 1:
ORA-01116: error in opening database file 5
ORA-01110: data file 5: '/data/oradata/ocrl/datafile/test.dbf'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3


SQL> exit
3.检查dbwr的进程PID
ocrl:/data/oradata/ocrl/datafile@oracle1>ps -ef|grep dbw0
oracle    6121     1  0 Feb07 ?        00:00:32 ora_dbw0_ocrl
oracle   19015 18603  0 11:52 pts/1    00:00:00 grep dbw0
4.dbwr会打开所有数据文件的句柄，在proc目录中可以查到，目录是进程PID，fd表示文件描述符
ocrl:/data/oradata/ocrl/datafile@oracle1>cd /proc/6121/fd
ocrl:/proc/6121/fd@oracle1>ls -l
total 0
lr-x------ 1 oracle dba 64 Feb  7 10:11 0 -> /dev/null
l-wx------ 1 oracle dba 64 Feb  7 10:11 1 -> /dev/null
l-wx------ 1 oracle dba 64 Feb  7 10:11 2 -> /dev/null
lrwx------ 1 oracle dba 64 Feb  7 10:11 256 -> /data/oradata/ocrl/control/control01.ctl
lrwx------ 1 oracle dba 64 Feb  7 10:11 257 -> /data/oradata/ocrl/control/control02.ctl
lrwx------ 1 oracle dba 64 Feb 10 11:42 258 -> /data/oradata/ocrl/datafile/system01.dbf
lrwx------ 1 oracle dba 64 Feb 10 11:42 259 -> /data/oradata/ocrl/datafile/sysaux01.dbf
lrwx------ 1 oracle dba 64 Feb 10 11:42 260 -> /data/oradata/ocrl/datafile/undotbs01.dbf
lrwx------ 1 oracle dba 64 Feb 10 11:42 261 -> /data/oradata/ocrl/datafile/users01.dbf
lrwx------ 1 oracle dba 64 Feb 10 11:42 262 -> /data/oradata/ocrl/datafile/test.dbf (deleted)
lrwx------ 1 oracle dba 64 Feb 10 11:42 263 -> /data/oradata/ocrl/tempfile/temp01.dbf
lr-x------ 1 oracle dba 64 Feb  7 10:11 3 -> /dev/null
lr-x------ 1 oracle dba 64 Feb  7 10:11 4 -> /u01/app/oracle/product/12.1.0/db_1/rdbms/mesg/oraus.msb
lr-x------ 1 oracle dba 64 Feb  7 10:11 5 -> /proc/6121/fd
lrwx------ 1 oracle dba 64 Feb  7 10:11 6 -> /u01/app/oracle/product/12.1.0/db_1/dbs/hc_ocrl.dat
l-wx------ 1 oracle dba 64 Feb  7 10:11 7 -> /u01/app/oracle/product/12.1.0/db_1/rdbms/mesg/oraus.msb

lrwx------ 1 oracle dba 64 Feb  7 10:11 9 -> /u01/app/oracle/product/12.1.0/db_1/dbs/lkOCRL

注意：注意其中“/data/oradata/ocrl/datafile/test.dbf (deleted)”字样，表示该文件已经被删除
5.直接cp该句柄文件名回原位置
ocrl:/proc/6121/fd@oracle1>cp 262 /data/oradata/ocrl/datafile/test.dbf

ocrl:/proc/6121/fd@oracle1>ls
0  1  2  256  257  258  259  260  261  262  263  3  4  5  6  7  9
ocrl:/proc/6121/fd@oracle1>cd /data/oradata/ocrl/tempfile/
ocrl:/data/oradata/ocrl/tempfile@oracle1>cd /data/oradata/ocrl/datafile/
ocrl:/data/oradata/ocrl/datafile@oracle1>ls
sysaux01.dbf  system01.dbf  test.dbf  undotbs01.dbf  users01.dbf
6.进行数据文件recover--在归档模式下
ocrl:/data/oradata/ocrl/datafile@oracle1>sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Fri Feb 10 11:44:24 2017

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL> alter database datafile 5 offline;

Database altered.

SQL> recover datafile 5;
Media recovery complete.
SQL> alter database datafile 5 online;

Database altered.


SQL> select file#,name from v$datafile;

     FILE#
----------
NAME
--------------------------------------------------------------------------------
     1
/data/oradata/ocrl/datafile/system01.dbf

     2
/data/oradata/ocrl/datafile/sysaux01.dbf

     3
/data/oradata/ocrl/datafile/undotbs01.dbf


     FILE#
----------
NAME
--------------------------------------------------------------------------------
     4
/data/oradata/ocrl/datafile/users01.dbf

     5
/data/oradata/ocrl/datafile/test.dbf


SQL> create table t tablespace test as select * from dual;

Table created.


SQL> select * from t;

D
-
X

SQL> exit
至此完成数据文件恢复
在非归档模式下,需要shutdown后,进入mount模式,offline,recover,online,open
恢复的原理是，在Linux操作系统中，如果文件从操作系统级别被rm掉，之前打开该文件的进程仍然持有相应的文件句柄，所指向的文件仍然可以读写，并且该文件的文件描述符可以从/proc目录中获得。但是要注意的是，此时如果关闭数据库，则此句柄会消失，那么除了扫描磁盘进行文件恢复之外就没有其它方法了，因此在数据库出现问题的时候，如果不确认情况的复杂程度，千万不要随便关闭数据库。重启数据库往往是没有意义的，甚至是致命的