当前位置： 首页 > 备份与恢复 > 正文

一次RMAN还原慢的分析

备份与恢复 huangtingzhong 发布于 2014-09-22 00:43 1条评论

         下面是模拟同事在客户现场遇到的RMAN还原慢的情况，同事也只能在旁边干着急。因为备份与还原是由其它的备份工程师在操作，但是由于备份工程师的ORACLE技术能力，导致在还原数据库速度很慢。我们知道，RMAN备份与还原也是可以通过配置参数来提到性能，如果是通过备份软件，还可以通过调用备份软件的BUFFER来实现，多路复用等机制来优化，如果数据文件存放在ASM环境中，现在ORACLE可以自动优化RMAN相关的ORACLE参数。然后，这次同事遇到的RMAN还原慢的主要原因不是由于RMAN的参数，下面我们通过模拟要证明，是什么原因导致整个备份速度慢。

         这里将备份集存放在磁盘上，没有模拟磁带的情况。

1，环境介绍

www.htz.pw > select * from v$version;

BANNER
--------------------------------------------------------------------------------
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 64-bit Windows: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production
www.htz.pw > host uname -a
windows32 luoping 2.6.1 7601 i686-pc Intel unknown MinGW

2，测试数据创建

这里创建了多个表空间，用于模拟生产环境

1，创建多个表空间
create tablespace htz01 datafile 'D:APPLUOPINGORADATAHTZHTZ01.DBF' size 10M;
.............
create tablespace htz25 datafile 'D:APPLUOPINGORADATAHTZHTZ25.DBF' size 10M;

创建测试表
create table htz.htz01 tablespace htz01 as select * from dba_objects;
....................
create table htz.htz25 tablespace htz25 as select * from dba_objects;

3,配置归档

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area  392495104 bytes
Fixed Size                  2255544 bytes
Variable Size             155190600 bytes
Database Buffers          226492416 bytes
Redo Buffers                8556544 bytes
Database mounted.
SQL> alter database archivelog;
Database altered.
SQL> alter database open;
Database altered.

4，配置备份脚本

由于备份脚本的内容太多，就不贴出来了，只贴了rman的命令

RUN {
ALLOCATE CHANNEL ch00 TYPE DISK;
ALLOCATE CHANNEL ch01 TYPE DISK;
BACKUP
      INCREMENTAL Level=0
      FORMAT 'd:shellbk_u{ff392285dba4c735eaf57cbf839a563e19e0ca0b993d821097d934f85a596e2c}u_s{ff392285dba4c735eaf57cbf839a563e19e0ca0b993d821097d934f85a596e2c}s_p{ff392285dba4c735eaf57cbf839a563e19e0ca0b993d821097d934f85a596e2c}p_t{ff392285dba4c735eaf57cbf839a563e19e0ca0b993d821097d934f85a596e2c}t'
      DATABASE;
sql 'alter system archive log current';
RELEASE CHANNEL ch00;
RELEASE CHANNEL ch01;
# Backup all archive logs
ALLOCATE CHANNEL ch00 TYPE DISK;
BACKUP
      FILESPERSET 20
      FORMAT 'd:shellarch-s{ff392285dba4c735eaf57cbf839a563e19e0ca0b993d821097d934f85a596e2c}s-p{ff392285dba4c735eaf57cbf839a563e19e0ca0b993d821097d934f85a596e2c}p-t{ff392285dba4c735eaf57cbf839a563e19e0ca0b993d821097d934f85a596e2c}t'
      ARCHIVELOG ALL;
RELEASE CHANNEL ch00;
ALLOCATE CHANNEL ch00 TYPE DISK;
BACKUP
      FORMAT 'd:shellcntrl_p_t'
      CURRENT CONTROLFILE;
RELEASE CHANNEL ch00;
}

d:shell>hot_database.cmd
RMAN> 2> 3> 4> 5> 6> 7> 8> 9> 10> 11> 12> 13> 14> 15> 16> 17> 18> 19> 20> 21> 22> 23> RMAN> LOGMSGDATERMAN_LOG_FILE

rman备份日志输出内容

==== started on 2014/09/21 周日  23:53 ====
Script name: hot_database.cmd

Recovery Manager: Release 11.2.0.3.0 - Production on Sun Sep 21 23:53:06 2014

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: HTZ (DBID=1913545637)
using target database control file instead of recovery catalog

RMAN> 2> 3> 4> 5> 6> 7> 8> 9> 10> 11> 12> 13> 14> 15> 16> 17> 18> 19> 20> 21> 22> 23>
allocated channel: ch00
channel ch00: SID=134 device type=DISK

allocated channel: ch01
channel ch01: SID=199 device type=DISK

Starting backup at 2014-09-21:23:53:07
channel ch00: starting incremental level 0 datafile backup set
channel ch00: specifying datafile(s) in backup set
input datafile file number=00001 name=D:APPLUOPINGORADATAHTZSYSTEM01.DBF
input datafile file number=00012 name=D:APPLUOPINGORADATAHTZHTZ08.DBF
input datafile file number=00014 name=D:APPLUOPINGORADATAHTZHTZ10.DBF
input datafile file number=00016 name=D:APPLUOPINGORADATAHTZHTZ12.DBF
input datafile file number=00018 name=D:APPLUOPINGORADATAHTZHTZ14.DBF
input datafile file number=00020 name=D:APPLUOPINGORADATAHTZHTZ16.DBF
input datafile file number=00022 name=D:APPLUOPINGORADATAHTZHTZ18.DBF
input datafile file number=00023 name=D:APPLUOPINGORADATAHTZHTZ19.DBF
input datafile file number=00024 name=D:APPLUOPINGORADATAHTZHTZ20.DBF
input datafile file number=00025 name=D:APPLUOPINGORADATAHTZHTZ21.DBF
input datafile file number=00026 name=D:APPLUOPINGORADATAHTZHTZ22.DBF
input datafile file number=00027 name=D:APPLUOPINGORADATAHTZHTZ23.DBF
input datafile file number=00028 name=D:APPLUOPINGORADATAHTZHTZ24.DBF
input datafile file number=00029 name=D:APPLUOPINGORADATAHTZHTZ25.DBF
channel ch00: starting piece 1 at 2014-09-21:23:53:07
channel ch01: starting incremental level 0 datafile backup set
channel ch01: specifying datafile(s) in backup set
input datafile file number=00002 name=D:APPLUOPINGORADATAHTZSYSAUX01.DBF
input datafile file number=00003 name=D:APPLUOPINGORADATAHTZUNDOTBS01.DBF
input datafile file number=00004 name=D:APPLUOPINGORADATAHTZUSERS01.DBF
input datafile file number=00005 name=D:APPLUOPINGORADATAHTZHTZ01.DBF
input datafile file number=00006 name=D:APPLUOPINGORADATAHTZHTZ02.DBF
input datafile file number=00007 name=D:APPLUOPINGORADATAHTZHTZ03.DBF
input datafile file number=00008 name=D:APPLUOPINGORADATAHTZHTZ04.DBF
input datafile file number=00009 name=D:APPLUOPINGORADATAHTZHTZ05.DBF
input datafile file number=00010 name=D:APPLUOPINGORADATAHTZHTZ06.DBF
input datafile file number=00011 name=D:APPLUOPINGORADATAHTZHTZ07.DBF
input datafile file number=00013 name=D:APPLUOPINGORADATAHTZHTZ09.DBF
input datafile file number=00015 name=D:APPLUOPINGORADATAHTZHTZ11.DBF
input datafile file number=00017 name=D:APPLUOPINGORADATAHTZHTZ13.DBF
input datafile file number=00019 name=D:APPLUOPINGORADATAHTZHTZ15.DBF
input datafile file number=00021 name=D:APPLUOPINGORADATAHTZHTZ17.DBF
channel ch01: starting piece 1 at 2014-09-21:23:53:08
channel ch00: finished piece 1 at 2014-09-21:23:53:23
piece handle=D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987 tag=TAG20140921T235307 comment=NONE
channel ch00: backup set complete, elapsed time: 00:00:16
channel ch00: starting incremental level 0 datafile backup set
channel ch00: specifying datafile(s) in backup set
channel ch01: finished piece 1 at 2014-09-21:23:53:23
piece handle=D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987 tag=TAG20140921T235307 comment=NONE
channel ch01: backup set complete, elapsed time: 00:00:15
channel ch01: starting incremental level 0 datafile backup set
channel ch01: specifying datafile(s) in backup set
including current SPFILE in backup set
channel ch01: starting piece 1 at 2014-09-21:23:53:23
including current control file in backup set
channel ch00: starting piece 1 at 2014-09-21:23:53:24
channel ch01: finished piece 1 at 2014-09-21:23:53:24
piece handle=D:SHELLBK_U0IPJ3JFJ_S18_P1_T858902003 tag=TAG20140921T235307 comment=NONE
channel ch01: backup set complete, elapsed time: 00:00:01
channel ch00: finished piece 1 at 2014-09-21:23:53:25
piece handle=D:SHELLBK_U0HPJ3JFJ_S17_P1_T858902003 tag=TAG20140921T235307 comment=NONE
channel ch00: backup set complete, elapsed time: 00:00:01
Finished backup at 2014-09-21:23:53:25

通过日志，可以看到生成了2个备份片的信息

5，还原测试

同样由于还原脚本内容太多，这里只贴了还原命令

5.1 备份工程师还原脚本模拟

RUN {
ALLOCATE CHANNEL ch00 TYPE DISK;
ALLOCATE CHANNEL ch01 TYPE DISK;
RESTORE DATAFILE 1 ;
RESTORE DATAFILE 2 ;
RESTORE DATAFILE 3 ;
RESTORE DATAFILE 4 ;
RESTORE DATAFILE 5 ;
RESTORE DATAFILE 6 ;
RESTORE DATAFILE 7 ;
RESTORE DATAFILE 8 ;
RESTORE DATAFILE 9 ;
RESTORE DATAFILE 10;
RESTORE DATAFILE 11;
RESTORE DATAFILE 12;
RESTORE DATAFILE 13;
RESTORE DATAFILE 14;
RESTORE DATAFILE 15;
RESTORE DATAFILE 16;
RESTORE DATAFILE 17;
RESTORE DATAFILE 18;
RESTORE DATAFILE 19;
RESTORE DATAFILE 20;
RESTORE DATAFILE 21;
RESTORE DATAFILE 22;
RESTORE DATAFILE 23;
RESTORE DATAFILE 24;
RESTORE DATAFILE 25;
RESTORE DATAFILE 26;
RESTORE DATAFILE 27;
RESTORE DATAFILE 28;
RESTORE DATAFILE 29;
RELEASE CHANNEL ch00;
RELEASE CHANNEL ch01;
}
d:shell>restore.cmd
RMAN> 2> 3> 4> 5> 6> 7> 8> 9> 10> 11> 12> 13> 14> 15> 16> 17> 18> 19> 20> 21> 22> 23> 24> 25> 26> 27> 28> 29> 30> 31> 32> 33> 34> 35> RMAN> LOGMSGDATERMAN_LOG_FILE

这里可以看到，每个数据文件都是一个单独的restore来还原。

下面来看看生成的日志内容

==== started on 2014/09/21 周日  23:59 ====
Script name: restore.cmd

Recovery Manager: Release 11.2.0.3.0 - Production on Sun Sep 21 23:59:14 2014

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: HTZ (DBID=1913545637, not open)
using target database control file instead of recovery catalog

RMAN> 2> 3> 4> 5> 6> 7> 8> 9> 10> 11> 12> 13> 14> 15> 16> 17> 18> 19> 20> 21> 22> 23> 24> 25> 26> 27> 28> 29> 30> 31> 32> 33> 34> 35>
allocated channel: ch00
channel ch00: SID=129 device type=DISK

allocated channel: ch01
channel ch01: SID=192 device type=DISK

Starting restore at 2014-09-21:23:59:15

channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00001 to D:APPLUOPINGORADATAHTZSYSTEM01.DBF
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:07
Finished restore at 2014-09-21:23:59:23

......
channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00007 to D:APPLUOPINGORADATAHTZHTZ03.DBF
channel ch00: reading from backup piece D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:01
Finished restore at 2014-09-21:23:59:32

Starting restore at 2014-09-21:23:59:32

channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00008 to D:APPLUOPINGORADATAHTZHTZ04.DBF
channel ch00: reading from backup piece D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:01
Finished restore at 2014-09-21:23:59:33

Starting restore at 2014-09-21:23:59:33

channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00009 to D:APPLUOPINGORADATAHTZHTZ05.DBF
channel ch00: reading from backup piece D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:01
Finished restore at 2014-09-21:23:59:34

Starting restore at 2014-09-21:23:59:34

channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00010 to D:APPLUOPINGORADATAHTZHTZ06.DBF
channel ch00: reading from backup piece D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:01
Finished restore at 2014-09-21:23:59:35

Starting restore at 2014-09-21:23:59:35

channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00011 to D:APPLUOPINGORADATAHTZHTZ07.DBF
channel ch00: reading from backup piece D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:01
Finished restore at 2014-09-21:23:59:36

Starting restore at 2014-09-21:23:59:36

channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00012 to D:APPLUOPINGORADATAHTZHTZ08.DBF
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:01
Finished restore at 2014-09-21:23:59:37

Starting restore at 2014-09-21:23:59:37

channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00013 to D:APPLUOPINGORADATAHTZHTZ09.DBF
channel ch00: reading from backup piece D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:01
Finished restore at 2014-09-21:23:59:39

Starting restore at 2014-09-21:23:59:39

channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00014 to D:APPLUOPINGORADATAHTZHTZ10.DBF
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:01
Finished restore at 2014-09-21:23:59:40

Starting restore at 2014-09-21:23:59:40

channel ch00: starting datafile backup set restore
channel ch00: specifying datafile(s) to restore from backup set
channel ch00: restoring datafile 00015 to D:APPLUOPINGORADATAHTZHTZ11.DBF
channel ch00: reading from backup piece D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987
channel ch00: piece handle=D:SHELLBK_U0GPJ3JF3_S16_P1_T858901987 tag=TAG20140921T235307
channel ch00: restored backup piece 1
channel ch00: restore complete, elapsed time: 00:00:01
Finished restore at 2014-09-21:23:59:41
.......................

其中一个备份片来看

channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987
channel ch00: reading from backup piece D:SHELLBK_U0FPJ3JF3_S15_P1_T858901987

在整个还原中，读了这么多次备份片，因为每一个restore命令就会去读还原片的信息，这就是慢的原因所在了。特别是在生产环境中，都是备份到磁带中的，还原不慢才怪。 

下面计算一下还原的时间

Starting restore at 2014-09-21:23:59:15
Finished restore at 2014-09-21:23:59:57

第一次还原使用了42S的时间，因为BUFFER的影响，多次测试，时间都差不多。

5.2 使用一条命令来还原

RUN {
ALLOCATE CHANNEL ch00 TYPE DISK;
ALLOCATE CHANNEL ch01 TYPE DISK;
RESTORE DATABASE;
RELEASE CHANNEL ch00;
RELEASE CHANNEL ch01;
}
d:shell>restore.cmd
RMAN> 2> 3> 4> 5> 6> 7> RMAN> LOGMSGDATERMAN_LOG_FILE

后台日志内容如下：

cript name: restore.cmd

Recovery Manager: Release 11.2.0.3.0 - Production on Mon Sep 22 00:06:23 2014

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: HTZ (DBID=1913545637, not open)
using target database control file instead of recovery catalog

RMAN> 2> 3> 4> 5> 6> 7>
allocated channel: ch00
channel ch00: SID=129 device type=DISK

allocated channel: ch01
channel ch01: SID=191 device type=DISK

Starting restore at 2014-09-22:00:06:24
....................

还原的时间，每一次测试

Starting restore at 2014-09-22:00:35:51
Finished restore at 2014-09-22:00:36:07

第二次测试

Starting restore at 2014-09-22:00:37:06
Finished restore at 2014-09-22:00:37:23

这里看到两次的时间都不到20S，远远小于之前的时间。

6，实验总结

在做rman还原的时候，尽量把命令写在一个restore命令中，减少对相同备份片进行重复的读取工作。另外整个实验需要注意的是：没有考虑一个数据文件写到一个备份片的情况。

赏

您可能还会对这些文章感兴趣！

一次RMAN还原慢的分析：目前有 1 条评论

  1. csdw
    沙发
    csdw
    2014-09-24 20:19

    哈哈,,黄大师,总结得好

    回复

发表评论

gravatar

? razz sad evil ! smile oops grin eek shock ??? cool lol mad twisted roll wink idea arrow neutral cry mrgreen

快捷键：Ctrl+Enter