分类目录归档：数据库

忘记执行end backup命令数据库恢复

发表于 2012 年 6 月 5 日 由 惜分飞

遇到两次begin backup忘记end backup导致的悲剧.虽然不是自己亲身经历,但是感触很深,这里做了一个小实验,说明在begin backup后忘记end backup,而又丢失了备份归档日志,且数据库异常重启的事故恢复(这里为了加大实验难道,并且使用begin backup命令后的热备文件恢复)
模拟begin end

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/xifenfei/archive
Oldest online log sequence     37
Next log sequence to archive   39
Current log sequence           39
SQL> alter tablespace bbed begin backup;

Tablespace altered.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/xifenfei/archive
Oldest online log sequence     37
Next log sequence to archive   39
Current log sequence           39
SQL> drop table chf.t_xff;

Table dropped.

SQL> create table chf.t_xff
  2    as
  3  select * from dba_objects;

Table created.

SQL> alter system switch logfile;

System altered.

SQL>   delete from chf.t_XFF;

30811 rows deleted.

SQL>   commit;

Commit complete.

SQL>   alter system  switch logfile;

System altered.

SQL> /

System altered.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/xifenfei/archive
Oldest online log sequence     40
Next log sequence to archive   42
Current log sequence           42

cp备份文件

[oracle@xifenfei xifenfei]$ cp bbed01.dbf bbed01.dbf_05
[oracle@xifenfei xifenfei]$ cp bbed02.dbf bbed02.dbf_05

继续操作数据库

SQL> alter system switch logfile;

System altered.

SQL>   insert into chf.t_xff
  2    select * from dba_objects;

30811 rows created.

SQL> commit;

Commit complete.

SQL>  archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u01/oracle/oradata/xifenfei/archive
Oldest online log sequence     41
Next log sequence to archive   43
Current log sequence           43
SQL> alter system switch logfile;

System altered.

模拟异常关闭数据库

SQL> shutdown immediate;
ORA-01149: cannot shutdown - file 11 has online backup set
ORA-01110: data file 11: '/u01/oracle/oradata/xifenfei/bbed01.dbf'
SQL> shutdown abort;
ORACLE instance shut down.

删除部分归档日志(模拟归档日志丢失)

[oracle@xifenfei archive]$ mv 1_39.dbf 1_39.dbf_bak
[oracle@xifenfei archive]$ mv 1_40.dbf 1_40.dbf_bak

启动数据库

[oracle@xifenfei xifenfei]$ sqlplus "/ as sysdba"

SQL*Plus: Release 9.2.0.4.0 - Production on Tue Jun 5 03:02:56 2012

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area  353441008 bytes
Fixed Size                   451824 bytes
Variable Size             184549376 bytes
Database Buffers          167772160 bytes
Redo Buffers                 667648 bytes
Database mounted.
ORA-01113: file 11 needs media recovery
ORA-01110: data file 11: '/u01/oracle/oradata/xifenfei/bbed01.dbf'

分析相关SCN

SQL> select file#,online_status "STATUS",to_char(change#,'9999999999999999') "SCN",
  2  To_char(time,'yyyy-mm-dd hh24:mi:ss')"TIME" from v$recover_file;

     FILE# STATUS  SCN               TIME
---------- ------- ----------------- -------------------
        11 ONLINE     12286828683164 2012-06-05 02:55:43
        12 ONLINE     12286828683164 2012-06-05 02:55:43

SQL> select file#,to_char(checkpoint_change#,'999999999999999') "SCN",
  2  to_char(last_change#,'999999999999999')"STOP_SCN" from v$datafile;

     FILE# SCN              STOP_SCN
---------- ---------------- ----------------
         1   12286828684636
         2   12286828684636
         3   12286828684636
         4   12286828684636
         5   12286828684636
         6   12286828684636
         7   12286828684636
         8   12286828684636
         9   12286828684636
        10   12286828684636
        11   12286828683164
        12   12286828683164

12 rows selected.

SQL> select file#,to_char(checkpoint_change#,'9999999999999999') "SCN",
  2  to_char(RESETLOGS_CHANGE#,'9999999999999999') "RESETLOGS SCN"
  3  from v$datafile_header;

     FILE# SCN               RESETLOGS SCN
---------- ----------------- -----------------
         1    12286828684636            174968
         2    12286828684636            174968
         3    12286828684636            174968
         4    12286828684636            174968
         5    12286828684636            174968
         6    12286828684636            174968
         7    12286828684636            174968
         8    12286828684636            174968
         9    12286828684636            174968
        10    12286828684636            174968
        11    12286828683164            174968
        12    12286828683164            174968

12 rows selected.

SQL> select file#,to_char(CHANGE#,'9999999999999999') "SCN",
  2  to_char(TIME,'yyyy-mm-dd hh24:mi:ss') "TIME" from v$backup;

     FILE# SCN               TIME
---------- ----------------- -------------------
         1                 0
         2                 0
         3                 0
         4                 0
         5                 0
         6                 0
         7                 0
         8                 0
         9                 0 
        10                 0
        11    12286828683164 2012-06-05 02:55:43
        12    12286828683164 2012-06-05 02:55:43

12 rows selected.

发现数据库未end backup

Tue Jun  5 02:55:43 2012
alter tablespace bbed begin backup
Tue Jun  5 02:55:43 2012
Completed: alter tablespace bbed begin backup

尝试end backup
出现这个错误是正常的,因为我替换回来的bbed表空间数据文件的版本信息可能和控制文件的不一致,解决方法是重建控制文件

SQL> alter tablespace bbed end backup;
alter tablespace bbed end backup
*
ERROR at line 1:
ORA-01235: END BACKUP failed for 2 file(s) and succeeded for 0
ORA-01122: database file 12 failed verification check
ORA-01110: data file 12: '/u01/oracle/oradata/xifenfei/bbed02.dbf'
ORA-01208: data file is an old version - not accessing current version
ORA-01122: database file 11 failed verification check
ORA-01110: data file 11: '/u01/oracle/oradata/xifenfei/bbed01.dbf'
ORA-01208: data file is an old version - not accessing current version

重建控制文件

SQL> shutdown abort;
ORACLE instance shut down.
SQL> STARTUP NOMOUNT
Total System Global Area  353441008 bytes
Fixed Size                   451824 bytes
Variable Size             184549376 bytes
Database Buffers          167772160 bytes
Redo Buffers                 667648 bytes

SQL>@ctl.sql
Control file created.

尝试恢复数据库

SQL> recover database;
ORA-00279: change 12286828683164 generated at 06/05/2012 02:55:43 needed for
thread 1
ORA-00289: suggestion : /u01/oracle/oradata/xifenfei/archive/1_39.dbf
ORA-00280: change 12286828683164 for thread 1 is in sequence #39


Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
auto
ORA-00308: cannot open archived log
'/u01/oracle/oradata/xifenfei/archive/1_39.dbf'
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3


ORA-00308: cannot open archived log
'/u01/oracle/oradata/xifenfei/archive/1_39.dbf'
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3

执行end backup

SQL> alter tablespace bbed end backup;

Tablespace altered.

再次查看相关SCN
可以发现end backup之后,datafile header 的scn发生了改变,说明begin backup主要是冻住了datafile header scn

SQL> select file#,online_status "STATUS",to_char(change#,'9999999999999999') "SCN",
  2  To_char(time,'yyyy-mm-dd hh24:mi:ss')"TIME" from v$recover_file;

     FILE# STATUS  SCN               TIME
---------- ------- ----------------- -------------------
         1 ONLINE     12286828684636 2012-06-05 03:00:46
         2 ONLINE     12286828684636 2012-06-05 03:00:46
         3 ONLINE     12286828684636 2012-06-05 03:00:46
         4 ONLINE     12286828684636 2012-06-05 03:00:46
         5 ONLINE     12286828684636 2012-06-05 03:00:46
         6 ONLINE     12286828684636 2012-06-05 03:00:46
         7 ONLINE     12286828684636 2012-06-05 03:00:46
         8 ONLINE     12286828684636 2012-06-05 03:00:46
         9 ONLINE     12286828684636 2012-06-05 03:00:46
        10 ONLINE     12286828684636 2012-06-05 03:00:46
        11 ONLINE     12286828683821 2012-06-05 02:56:26
        12 ONLINE     12286828683821 2012-06-05 02:56:26

12 rows selected.

SQL> select file#,to_char(checkpoint_change#,'999999999999999') "SCN",
  2  to_char(last_change#,'999999999999999')"STOP_SCN" from v$datafile;

     FILE# SCN              STOP_SCN
---------- ---------------- ----------------
         1   12286828684636
         2   12286828684636
         3   12286828684636
         4   12286828684636
         5   12286828684636
         6   12286828684636
         7   12286828684636
         8   12286828684636
         9   12286828684636
        10   12286828684636
        11   12286828684636
        12   12286828684636

12 rows selected.

SQL> select file#,to_char(checkpoint_change#,'9999999999999999') "SCN",
  2  to_char(RESETLOGS_CHANGE#,'9999999999999999') "RESETLOGS SCN"
  3  from v$datafile_header;

     FILE# SCN               RESETLOGS SCN
---------- ----------------- -----------------
         1    12286828684636            174968
         2    12286828684636            174968
         3    12286828684636            174968
         4    12286828684636            174968
         5    12286828684636            174968
         6    12286828684636            174968
         7    12286828684636            174968
         8    12286828684636            174968
         9    12286828684636            174968
        10    12286828684636            174968
        11    12286828683821            174968
        12    12286828683821            174968

12 rows selected.

再次尝试恢复数据库

SQL> recover database;
ORA-00279: change 12286828683821 generated at 06/05/2012 02:56:26 needed for
thread 1
ORA-00289: suggestion : /u01/oracle/oradata/xifenfei/archive/1_41.dbf
ORA-00280: change 12286828683821 for thread 1 is in sequence #41


Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
auto
Log applied.
Media recovery complete.
SQL> alter database open;

Database altered.

总结说明
在数据库忘记end backup,而又被异常重启数据库时候,会提示你需要恢复.这个时候如果你有所有的归档日志,那没有任何问题,直接recover就可以了.如果因为begin backup命令执行比较久,部分归档日志丢失,这个时候不能直接recover,可以先尝试end backup,然后在recover.如果在这个时候还发现有部分日志不存在,那只能考虑bbed修改datafile header的scn.
温馨提醒:各位dba在执行begin backup之后一定要记得end backup

发表在 Oracle备份恢复 | 评论关闭

ORACLE最大可以存储多少数据量

发表于 2012 年 6 月 4 日 由 惜分飞

今天有朋友在群里面讨论oracle数据库最大可以存储的数据大小,下面根据官方文档提供的相关限制,大概估算出来oracle数据库最多可以存储的数据量

Physical Database Limits(11.2)

Item

Type of Limit

Limit Value

Database Block Size

Minimum

2048 bytes; must be a multiple of operating system physical block size

Database Block Size

Maximum

Operating system dependent; never more than 32 KB

Database Blocks

Minimum in initial extent of a segment

2 blocks

Database Blocks

Maximum per datafile

Platform dependent; typically 222 - 1 blocks

Controlfiles

Number of control files

1 minimum; 2 or more (on separate devices) strongly recommended

Controlfiles

Size of a control file

Dependent on operating system and database creation options; maximum of25,000 x (database block size)

Database files

Maximum per tablespace

Operating system dependent; usually 1022

Database files

Maximum per database

65533

May be less on some operating systems

Limited also by size of database blocks and by the DB_FILES initialization parameter for a particular instance

Database extents

Maximum per dictionary managed tablespace

4 GB * physical block size (with K/M modifier); 4 GB (without K/M modifier)

Database extents

Maximum per locally managed (uniform) tablespace

2 GB * physical block size (with K/M modifier); 2 GB (without K/M modifier)

Database file size

Maximum

Operating system dependent. Limited by maximum operating system file size; typically 222 or 4 MB blocks

MAXEXTENTS

Default value

Derived from tablespace default storage or DB_BLOCK_SIZE initialization parameter

MAXEXTENTS

Maximum

Unlimited

Redo Log Files

Maximum number of logfiles

Limited by value of MAXLOGFILES parameter in the CREATE DATABASE statement

Control file can be resized to allow more entries; ultimately an operating system limit

Redo Log Files

Maximum number of logfiles per group

Unlimited

Redo Log File Size

Minimum size

4 MB

Redo Log File Size

Maximum Size

Operating system limit; typically 2 GB

Tablespaces

Maximum number per database

64 K

Number of tablespaces cannot exceed the number of database files because each tablespace must include at least one file

Bigfile Tablespaces

Number of blocks

A bigfile tablespace contains only one datafile or tempfile, which can contain up to approximately 4 billion ( 232 ) blocks. The maximum size of the single datafile or tempfile is 128 terabytes (TB) for a tablespace with 32 K blocks and 32 TB for a tablespace with 8 K blocks.

Smallfile (traditional) Tablespaces

Number of blocks

A smallfile tablespace is a traditional Oracle tablespace, which can contain 1022 datafiles or tempfiles, each of which can contain up to approximately 4 million (222) blocks.

External Tables file

Maximum size

Dependent on the operating system.

An external table can be composed of multiple files.

通过这里的相关限制可以大概的技术出来oracle数据库在传统数据文件和大数据文件情况下最大大小分别是:

传统数据文件(Smallfile)

32*1024(数据块大小)* (222–1)(一个数据文件的数据块数)*65533

(数据库中最多数据文件个数)= 9006784790495232(byte)/1024/1024/1024/1024=8191.6P

如果按照我们常用的block_size=8k,那么我们的数据库可以存储大小为2047.9P

大数据文件(Bigfile)

32*1024(数据块大小)* (232– 1)(一个数据文件的数据块数)*65533

(数据库中最多数据文件个数) = 9222949822242324480 (byte)/1024/1024/1024/1024 =8589541374P

如果按照我们常用的block_size=8k,那么我们的数据库可以存储大小为2147385343.5P

参考:http://docs.oracle.com/cd/E11882_01/server.112/e25513/limits002.htm

发表在 Oracle | 一条评论

rman通过nfs备份

发表于 2012 年 6 月 3 日 由 惜分飞

挂载nfs

[root@xifenfei tmp]# mount -t nfs 192.168.1.90:/tmp/nfs /nfs
[root@xifenfei tmp]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              18G   12G  5.2G  70% /
tmpfs                 737M     0  737M   0% /dev/shm
/dev/sdb1              20G  7.8G   11G  42% /u01/oracle/oradata
192.168.1.90:/tmp/nfs
                       18G   13G  3.9G  77% /nfs

rman备份

[oracle@xifenfei nfs]$ rman target /

Recovery Manager: Release 10.2.0.1.0 - Production on Wed May 30 16:31:40 2012

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

connected to target database: XFF (DBID=3426707456)

RMAN> backup datafile 1 format '/nfs/rman/system01_%U';

Starting backup at 3-JUN-12
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=146 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 05/30/2012 16:32:17
ORA-19602: cannot backup or copy active file in NOARCHIVELOG mode
continuing other job steps, job failed will not be re-run
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
including current control file in backupset
including current SPFILE in backupset
channel ORA_DISK_1: starting piece 1 at 3-JUN-12
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 05/30/2012 16:32:20
ORA-19504: failed to create file "/nfs/rman/system01_02nc9rgh_1_1"
ORA-27054: NFS file system where the file is created or resides is not mounted with correct options
Additional information: 3

重新挂载nfs

[root@xifenfei ~]# umount /nfs
[root@xifenfei tmp]# mount -t nfs -o rw,bg,hard,rsize=32768,wsize=32768,
>vers=3,nointr,timeo=600,tcp 192.168.1.90:/tmp/nfs /nfs

rman重新备份

[oracle@xifenfei ~]$ rman target /

Recovery Manager: Release 10.2.0.1.0 - Production on Wed May 30 16:38:14 2012

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

connected to target database: XFF (DBID=3426707456)

RMAN> backup datafile 1 format '/nfs/rman/system01_%U';

Starting backup at 3-JUN-12
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=143 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00001 name=/u01/oracle/oradata/XFF/system01.dbf
channel ORA_DISK_1: starting piece 1 at 3-JUN-12
channel ORA_DISK_1: finished piece 1 at 3-JUN-12
piece handle=/nfs/rman/system01_07nc9rrv_1_1 tag=TAG20120530T163823 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:02:15
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
including current control file in backupset
including current SPFILE in backupset
channel ORA_DISK_1: starting piece 1 at 3-JUN-12
channel ORA_DISK_1: finished piece 1 at 3-JUN-12
piece handle=/nfs/rman/system01_08nc9s07_1_1 tag=TAG20120530T163823 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:02
Finished backup at 3-JUN-12

查看nfs源端文件

[root@xifenfei rman]# pwd
/tmp/nfs/rman
[root@xifenfei rman]# ls -l
total 378300
-rw-r-----  1 54321 54321 379846656 Jun  3 13:45 system01_07nc9rrv_1_1
-rw-r-----  1 54321 54321   7143424 Jun  3 13:45 system01_08nc9s07_1_1

要点说明
Mount Options for Oracle files when used with NFS on NAS devices [ID 359515.1]

发表在 rman备份/恢复 | 一条评论