物理Dg和逻辑dg的区别

Posted 2023-03-20

1、实现机制不同

一个是基于block的，一个是基于SQL statement。

物理dg是通过传日志的形式block对block的完全把主库复制，复制出来的从库和主库完全一样，

逻辑dg是通过传日志，再应用logmin的技术将日志中的sql挖出，处理，并重新执行。

2、功能不同

10g的物理dg只能只读打开，但11g可以读写打开，且从库名必须和主库名相同。

逻辑dg从库可以读写打开，逻辑dg有些表和数据是不能同步的，且主库和从库可以不完全相同。

3、同步方式不同

物理dg通过重做应用与主数据库保持同步，物理dg与主数据库SCN保持一致。

逻辑dg通过SQL应用与主数据库保持同步，逻辑dg只需要数据保持一致。

扩展资料：

一、DG的优点：

1、灾难恢复及高可用性。

2、全面的数据保护。

3、有效利用系统资源。

4、在高可用及高性能之间更加灵活的平衡机制。

5、故障自动检查及解决方案。

6、集中的、易用的管理模式。

7、自动化的角色转换。

二、DG的缺点：

1、由于传输整个日志文件，所以，需要较高的网络传输带宽。

2、在Oracle 11g之前的物理备库虽然可以以只读方式打开，然后执行查询、报表等操作，但需要停止应用日志，这将使目标库与源数据不能保持同步，如果在此期间源数据库发生故障，那么将延长切换的时间。

从Oracle 11g开始，ADG可以在数据库打开的情况下应用日志，这极大地提高了DG的应用范围。

3、逻辑备库不能支持某些特定的数据对象和数据类型。

4、不支持双向复制，所以，无法应用于信息集成的场合。

5、只能复制整个数据库，不能选择某个SCHEMA或表空间或表进行单独复制。

6、不支持异构的系统环境，需要相同的操作系统版本和数据库版本（Oracle 11g支持部分异构平台）。

参考技术A 物理低格是重新划分磁道，扇区，高格仅仅是把不要的文件头写0而已（这个说得不是很严谨，还请诸位指正），出厂之后没有特殊情况不会再低格，因为它会损伤磁盘，而高格不会，你爱格几次都行

DG搭建方式区分

DG搭建三种方式：

 一、异机恢复，restore database,recover database

 二、 duplicate target database for standby from active database;

 三、 duplicate target database for standby

 

区别：

对主库的影响：

异机恢复，使用主库传输过来的备份，手工搭建物理DG，影响最小，安全系数最高，三种方式对比操作复杂   --手动挡

duplicate from active database 使用主库在线backup as copy 在线对主库数据文件进行操作系统拷贝备份，影响最大，安全系数最低，操作最简单  --自动驾驶

duplicate  fro standby 使用主库传输的备份进行恢复，与异机恢复在于，当主备文件路径不同时，可以使用参数，自动转换，而异机恢复 RMAN SET指定  ，影响也小，安全--半自动

 

 

 

#根据恢复应用及参数调整做出说明：

一、异机恢复方式：

1.1控制文件

 

#主库备份控制文件

RMAN> backup format ‘/u01/app/rman/control%U‘ current controlfile for standby;

#备库restore控制文件，从备份片中还原

RMAN> restore standby controlfile from ‘/picclife/app/rman/control1rsvlvau_1_1‘;

 

1.2日志文件目录修改 命令 ，执行修改--备库Mount状态下

 

# set linesize 200

set heading off

set feedback off

spool /home/oracle/rename.sql

 select ‘alter database rename file ‘‘‘||member||‘‘‘ to ‘||‘‘‘/picclife/app/oracle/oradata/ENV/‘||substr(member,instr(member,‘/‘,‘-1‘)+1)||‘‘‘‘||‘;‘ from v$logfile;

spool off

1.3数据文件修改路径--两种情况:

          date_file_1可以在数据库Mount状态直接alter database rename修改成功

          data_file_2 rename不成功，，在RMANrestore 还原数据文件，set指定路径

1.3.1 data_file_1=>

#执行，输出修改sql,执行操作

select ‘alter database rename file ‘‘‘||name||‘‘‘ to  ‘||‘‘‘/picclife/app/oracle/oradata/ENV/‘||substr(name,instr(name,‘/‘,‘-1‘)+1)||‘‘‘‘ ||‘;‘ from v$datafile;

 

1.3.2data_file_2=>

#如果上述操作：数据文件无法rename,则执行如下命令：输出SQL，不执行

>spool /home/oracle/newname.sql

select ‘set newname for datafile ‘||file#||‘ to "/picclife/app/oracle/oradata/ENV/‘||substr(name,instr(name,‘/‘,‘-1‘)+1)||‘";‘ from v$datafile;

 1.4 restore搭建备库

 

#可以使用RMAN中的newname，临时性：将restore还原的路径，修改为指定

#  switch datafile all;      ---永久性的，直接修改控制文件中记录的数据文件目录

RMAN> run{

allocate channel c1 type disk;

allocate channel c2 type disk;

allocate channel c3 type disk;

allocate channel c4 type disk;

set newname for datafile 1 to "/picclife/app/oracle/oradata/ENV/system01.dbf";

set newname for datafile 2 to "/picclife/app/oracle/oradata/ENV/sysaux01.dbf";

set newname for datafile 3 to "/picclife/app/oracle/oradata/ENV/undotbs01.dbf";

set newname for datafile 4 to "/picclife/app/oracle/oradata/ENV/users01.dbf";

set newname for datafile 5 to "/picclife/app/oracle/oradata/ENV/example01.dbf";

set newname for datafile 6 to "/picclife/app/oracle/oradata/ENV/test1";

set newname for datafile 7 to "/picclife/app/oracle/oradata/ENV/lin_tbs";

set newname for datafile 8 to "/picclife/app/oracle/oradata/ENV/undo_tb12.dbf";

set newname for datafile 9 to "/picclife/app/oracle/oradata/ENV/sink_tbs";

set newname for datafile 10 to "/picclife/app/oracle/oradata/ENV/index01.dbf";

set newname for datafile 11 to "/picclife/app/oracle/oradata/ENV/lmtbsb01.dbf";

set newname for datafile 12 to "/picclife/app/oracle/oradata/ENV/lmtbsb02.dbf";

set newname for datafile 13 to "/picclife/app/oracle/oradata/ENV/lmtbsb03.dbf";

set newname for datafile 14 to "/picclife/app/oracle/oradata/ENV/lmtbsb04.dbf";                                                                                                                       

set newname for datafile 15 to "/picclife/app/oracle/oradata/ENV/sm_a.dbf";

set newname for datafile 16 to "/picclife/app/oracle/oradata/ENV/bigts.big";

set newname for datafile 17 to "/picclife/app/oracle/oradata/ENV/rm_a.dbf";

set newname for datafile 18 to "/picclife/app/oracle/oradata/ENV/lmt.dbf";

set newname for datafile 19 to "/picclife/app/oracle/oradata/ENV/undo_tb14.db";

set newname for datafile 20 to "/picclife/app/oracle/oradata/ENV/compress.dbf";

set newname for datafile 21 to "/picclife/app/oracle/oradata/ENV/compressb.dbf";

set newname for datafile 22 to "/picclife/app/oracle/oradata/ENV/compressc.dbf";

set newname for datafile 23 to "/picclife/app/oracle/oradata/ENV/tbs_01.dbf";

set newname for datafile 24 to "/picclife/app/oracle/oradata/ENV/tbs_02.dbf";                                                  

set newname for datafile 25 to "/picclife/app/oracle/oradata/ENV/ceshi.dbf";

restore database;

 switch datafile all;

release channel c4；

release channel c3;

release channel c2;

release channel c1;

}

 

 

二、使用RMAN，backup as copy操作更简单，但是对主库可能有影响，无需主库备份，无需人工操作：

 

2.1备库参数设置：

#主备直接，路径转换参数：前主库文件路径，后备库文件路径

db_file_name_convert         

/u01/app/oracle/oradata/ENMO/,/picclife/app/oracle/oradata/dage/

log_file_name_convert             

/u01/app/oracle/oradata/ENMO/,/picclife/app/oracle/oradata/dage/

 

 

2.2直接在主库begin backup表空间，as copy tablespace传输至备库，end backup

duplicate target database for standby from active database;

 

2.3RMAN日志截取：

#操作系统密码文件自动拷贝

contents of Memory Script:
{   backup as copy reuse
   targetfile  ‘/u01/app/oracle/product/11.2.0/dbhome_1/dbs/orapwENMO‘ auxiliary format
 ‘/picclife/app/oracle/product/11.2.0/dbhome_1/dbs/orapwdage‘   ;}

#控制文件自动拷贝standby 至备库参数文件指定的控制文件名称及路径

contents of Memory Script:
{ backup as copy current controlfile for standby auxiliary format  ‘/picclife/app/oracle/oradata/dage/control01.ctl‘;}

#生成控制文件启动脚本，执行将备库启动到Mount状态

contents of Memory Script:
{ sql clone ‘alter database mount standby database‘;}
executing Memory Script

sql statement: alter database mount standby database

#根据参数文件db_file_name_convent参数指定转换，set newname指定新的路径

contents of Memory Script:
   set newname for tempfile  1 to
 "/picclife/app/oracle/oradata/dage/temp001.dbf";
   switch clone tempfile all;
   set newname for datafile  1 to
 "/picclife/app/oracle/oradata/dage/system01.dbf";
   set newname for datafile  2 to
 "/picclife/app/oracle/oradata/dage/sysaux01.dbf";
   set newname for datafile  3 to
 "/picclife/app/oracle/oradata/dage/undotbs01.dbf";
   set newname for datafile  4 to
 "/picclife/app/oracle/oradata/dage/users01.dbf";
   set newname for datafile  5 to
 "/picclife/app/oracle/oradata/dage/example01.dbf";

#对主库数据文件进行Backup as copy 操作系统拷贝备份，传输至备库指定路径
   backup as copy reuse
   datafile  1 auxiliary format
 "/picclife/app/oracle/oradata/dage/system01.dbf"   datafile
 2 auxiliary format
 "/picclife/app/oracle/oradata/dage/sysaux01.dbf"   datafile
 3 auxiliary format
 "/picclife/app/oracle/oradata/dage/undotbs01.dbf"   datafile
 4 auxiliary format
 "/picclife/app/oracle/oradata/dage/users01.dbf"   datafile
 5 auxiliary format
 "/picclife/app/oracle/oradata/dage/example01.dbf"   ;
   sql ‘alter system archive log current‘;
}
executing Memory Script

executing command: SET NEWNAME

renamed tempfile 1 to /picclife/app/oracle/oradata/dage/temp001.dbf in control file

executing command: SET NEWNAME

#省略部分日志，重复

executing command: SET NEWNAME

Starting backup at 15-JAN-18
using channel ORA_DISK_1
channel ORA_DISK_1: starting datafile copy
input datafile file number=00003 name=/u01/app/oracle/oradata/ENMO/undotbs01.dbf
output file name=/picclife/app/oracle/oradata/dage/undotbs01.dbf tag=TAG20180408T020947
channel ORA_DISK_1: datafile copy complete, elapsed time: 00:01:46

#省略部分日志，重复

sql statement: alter system archive log current

#执行修改控制文件中数据文件的路径：提交修改

contents of Memory Script:
{
   switch clone datafile all;
}
executing Memory Script

datafile 1 switched to datafile copy
input datafile copy RECID=1 STAMP=965518459 file name=/picclife/app/oracle/oradata/dage/system01.dbf
datafile 2 switched to datafile copy

#省略部分日志，重复

 

 三、使用RMAN，restore backup 使用备份集搭建物理DG，对主库影响小：

 

 3.1主库全备

 

run{ sql ‘alter system archive log current‘;
backup database format ‘/tmp/full/full_back_%U.bak‘;
backup format ‘/tmp/full/arch_%U.log‘ archivelog all delete input;
backup current controlfile for standby format=‘/tmp/full/contr_standby%U‘;}

 

3.2直接执行duplicate target database for standby报错：需要将主库的备份，传输至备库

#主库备份:且备份文件，备库能读取

 $ scp full/* [email protected]:/tmp/full

#修改权限：

# chown oracle.oinstall *

 

#再次执行 OK

  $ rman target sys/[email protected] auxiliary sys/[email protected]

duplicate target database for standby;

 

3.3日志

 

#使用备份的standby 控制文件
{restore clone standby controlfile;}
#从备份文件中提取备份信息

channel ORA_AUX_DISK_1: starting datafile backup set restore
channel ORA_AUX_DISK_1: restoring control file
channel ORA_AUX_DISK_1: reading from backup piece /tmp/full/contr_standby2osvpprb_1_1
channel ORA_AUX_DISK_1: piece handle=/tmp/full/contr_standby2osvpprb_1_1 tag=TAG20180408T031347
channel ORA_AUX_DISK_1: restored backup piece 1
channel ORA_AUX_DISK_1: restore complete, elapsed time: 00:00:03
output file name=/picclife/app/oracle/oradata/dage/control01.ctl
Finished restore at 16-JAN-18

#启动到mount状态
{  sql clone ‘alter database mount standby database‘;}
executing Memory Script

sql statement: alter database mount standby database

#根据参数文件，自动set newname restore还原目录

contents of Memory Script:
{
   set newname for tempfile  1 to
 "/picclife/app/oracle/oradata/dage/temp001.dbf";
   switch clone tempfile all;
   set newname for datafile  1 to
 "/picclife/app/oracle/oradata/dage/system01.dbf";
   set newname for datafile  2 to
 "/picclife/app/oracle/oradata/dage/sysaux01.dbf";
   set newname for datafile  3 to
 "/picclife/app/oracle/oradata/dage/undotbs01.dbf";
   set newname for datafile  4 to
 "/picclife/app/oracle/oradata/dage/users01.dbf";
   set newname for datafile  5 to
 "/picclife/app/oracle/oradata/dage/example01.dbf";
   restore
   clone database
   ;
}
executing Memory Script

executing command: SET NEWNAME

renamed tempfile 1 to /picclife/app/oracle/oradata/dage/temp001.dbf in control file

executing command: SET NEWNAME

#执行restore还原操作：从备份集中获取数据！！！

executing command: SET NEWNAME

Starting restore at 16-JAN-18
using channel ORA_AUX_DISK_1

channel ORA_AUX_DISK_1: starting datafile backup set restore
channel ORA_AUX_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_AUX_DISK_1: restoring datafile 00001 to /picclife/app/oracle/oradata/dage/system01.dbf
channel ORA_AUX_DISK_1: restoring datafile 00002 to /picclife/app/oracle/oradata/dage/sysaux01.dbf
channel ORA_AUX_DISK_1: restoring datafile 00003 to /picclife/app/oracle/oradata/dage/undotbs01.dbf
channel ORA_AUX_DISK_1: restoring datafile 00004 to /picclife/app/oracle/oradata/dage/users01.dbf
channel ORA_AUX_DISK_1: restoring datafile 00005 to /picclife/app/oracle/oradata/dage/example01.dbf
channel ORA_AUX_DISK_1: reading from backup piece /tmp/full/full_back_2lsvppp2_1_1.bak

#确认修改控制文件记录的数据文件目录及名称

contents of Memory Script:
{  switch clone datafile all;}
executing Memory Script

#还原操作完成

datafile 1 switched to datafile copy
input datafile copy RECID=2 STAMP=965685533 file name=/picclife/app/oracle/oradata/dage/system01.dbf
datafile 2 switched to datafile copy

 

 

 

 

 

 

*格式恶心。。。