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一次RMAN还原慢的分析

huangtingzhong 发布于 2014-09-22 00:43BACKUP & RESTORE1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:\APP\LUOPING\ORADATA\HTZ\HTZ01.DBF’ size 10M;

.…………

create tablespace htz25 datafile ‘D:\APP\LUOPING\ORADATA\HTZ\HTZ25.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:\shell\bk_u%u_s%s_p%p_t%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:\shell\arch-s%s-p%p-t%t’

      ARCHIVELOG ALL;

RELEASE CHANNEL ch00;

ALLOCATE CHANNEL ch00 TYPE DISK;

BACKUP

      FORMAT ‘d:\shell\cntrl_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:\APP\LUOPING\ORADATA\HTZ\SYSTEM01.DBF

input datafile file number=00012 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ08.DBF

input datafile file number=00014 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ10.DBF

input datafile file number=00016 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ12.DBF

input datafile file number=00018 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ14.DBF

input datafile file number=00020 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ16.DBF

input datafile file number=00022 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ18.DBF

input datafile file number=00023 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ19.DBF

input datafile file number=00024 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ20.DBF

input datafile file number=00025 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ21.DBF

input datafile file number=00026 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ22.DBF

input datafile file number=00027 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ23.DBF

input datafile file number=00028 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ24.DBF

input datafile file number=00029 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ25.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:\APP\LUOPING\ORADATA\HTZ\SYSAUX01.DBF

input datafile file number=00003 name=D:\APP\LUOPING\ORADATA\HTZ\UNDOTBS01.DBF

input datafile file number=00004 name=D:\APP\LUOPING\ORADATA\HTZ\USERS01.DBF

input datafile file number=00005 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ01.DBF

input datafile file number=00006 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ02.DBF

input datafile file number=00007 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ03.DBF

input datafile file number=00008 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ04.DBF

input datafile file number=00009 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ05.DBF

input datafile file number=00010 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ06.DBF

input datafile file number=00011 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ07.DBF

input datafile file number=00013 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ09.DBF

input datafile file number=00015 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ11.DBF

input datafile file number=00017 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ13.DBF

input datafile file number=00019 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ15.DBF

input datafile file number=00021 name=D:\APP\LUOPING\ORADATA\HTZ\HTZ17.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:\SHELL\BK_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:\SHELL\BK_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:\SHELL\BK_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:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\SYSTEM01.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\HTZ03.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0GPJ3JF3_S16_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\HTZ04.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0GPJ3JF3_S16_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\HTZ05.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0GPJ3JF3_S16_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\HTZ06.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0GPJ3JF3_S16_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\HTZ07.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0GPJ3JF3_S16_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\HTZ08.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\HTZ09.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0GPJ3JF3_S16_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\HTZ10.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\APP\LUOPING\ORADATA\HTZ\HTZ11.DBF

channel ch00: reading from backup piece D:\SHELL\BK_U0GPJ3JF3_S16_P1_T858901987

channel ch00: piece handle=D:\SHELL\BK_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:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_U0FPJ3JF3_S15_P1_T858901987

channel ch00: reading from backup piece D:\SHELL\BK_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。

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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

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