背景
之前发表过一篇Oracle 12c RAC到单机数据迁移的文章，介绍了Oracle 12c从RAC到单机的数据迁移过程，本文在此基础上继续介绍从单机到RAC的迁移过程。
阅读本文之前建议先阅读 Oracle 12c RAC到单机数据迁移了解相关知识点
实现
下文远程数据库指的是需要迁移的远程数据库，本地数据库指的是迁入的目标数据库
- 在远程数据库上创建用户，本地数据库将通过该用户创建dblink进行克隆
[oracle]$ sqlplus / as sysdba
SQL*Plus: Release 12.2.0.1.0 Production on Wed Jun 24 10:10:47 2020
Copyright (c) 1982, 2016, Oracle. All rights reserved.
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
SQL> show pdbs
CON_ID CON_NAME OPEN MODE RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED READ ONLY NO
3 HRPROD MOUNTED
SQL> alter session set container=HRPROD;
Session altered.
SQL> CREATE USER cloner IDENTIFIED BY oracle;
User created.
SQL> GRANT CREATE SESSION, CREATE PLUGGABLE DATABASE TO cloner;
Grant succeeded.
- 本地数据库新建连接描述符，修改tnsnames.ora
tnsnames.ora文件位于$ORACLE_HOME/network/admin目录下，如/home/oracle/app/oracle/product/12.2.0/dbhome_1/network/admin，如果目录下没有该文件就手动创建一个，向该文件添加远程数据库的连接(oracle用户)
HRPROD =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 172.16.11.6)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = HRPROD)
)
)- 本地数据库创建dblink
[oracle]$ sqlplus / as sysdba
SQL*Plus: Release 12.2.0.1.0 Production on Wed Jun 24 10:25:08 2020
Copyright (c) 1982, 2016, Oracle. All rights reserved.
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
SQL> drop database link XL1;
Database link dropped.
SQL> create database link XL1 connect to cloner identified by oracle using 'HRPROD';
Database link created.
SQL> desc user_tables@XL1; 如果desc user_tables@XL1能正常返回说明连接正常
- 将远程数据修改为只读模式
[oracle]$ sqlplus / as sysdba
SQL*Plus: Release 12.2.0.1.0 Production on Wed Jun 24 10:35:22 2020
Copyright (c) 1982, 2016, Oracle. All rights reserved.
Connected to:
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
SQL> alter pluggable database HRPROD close;
Pluggable database altered.
SQL> alter pluggable database HRPROD open read only;
Pluggable database altered. 如果alter pluggable database HRPROD close;长时间未响应，可以直接进入数据库执行shutdown命令，效果是一样的
SQL> alter session set container=HRPROD
SQL> shutdown immediate; - 本地数据库创建datafile目录
由于目标数据库是RAC，RAC存储方式采用共享存储，并且通过ASM做磁盘管理，我们需要预先在asm中创建好datafile目录，通过asmcmd命令可以对asm磁盘进行管理
[oracle]$ asmcmd
ASMCMD> ls
ARCH/
DATA/
GIMR/
OCR/
ASMCMD> cd DATA/DEMO/DATAFILE
ASMCMD> mkdir HRPROD
ASMCMD> cd ../TEMPFILE
ASMCMD> mkdir HRPROD
ASMCMD> ls
HRPROD/
ASMCMD> exitasmcmd命令跟linux磁盘操作命令类似，并不复杂。
- 本地数据库执行clone命令
在RAC到单机的迁移过程中，通过dblink统一做一次file_name_convert就行，但单机迁RAC必须对所有的datafile进行单独转换，你可以登录到源数据库执行以下命令查询所有的datafile
SQL> select file_name from dba_data_files;
FILE_NAME
--------------------------------------------------------------------------------
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/system.274.1027852675
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/sysaux.275.1027852675
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/undotbs1.273.1027852675
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/undo_2.277.1027852725
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/users.278.1027852727
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_ias_portlet.279.1028114765
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_wls.280.1028114765
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_iau.281.1028114765
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_mds.282.1028114767
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_stb.283.1028114767
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_ias_opss.284.1028114767
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_ias_activity.285.1028114769
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_ias_webcenter.286.1028114771
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_wls.288.1028125223
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_ias_ums.289.1028125223
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_stb.290.1028125225
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_mds.291.1028125225
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_iau.293.1028125227
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_ias_opss.294.1028125227
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_soainfra.295.1028125229
--------------------------------------------------------------------------------
/home/oracle/app/oracle/product/12.2.0/dbhome_1/dbs/MISSING00092
21 rows selected那么clone命令如下
create pluggable database HRPROD from HRPROD@XL1 file_name_convert=('/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_ias_activity.285.1028114769','+DATA/DEMO/DATAFILE/HRPROD/portal_ias_activity.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_ias_opss.284.1028114767','+DATA/DEMO/DATAFILE/HRPROD/portal_ias_opss.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_ias_portlet.279.1028114765','+DATA/DEMO/DATAFILE/HRPROD/portal_ias_portlet.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_ias_webcenter.286.1028114771','+DATA/DEMO/DATAFILE/HRPROD/portal_ias_webcenter.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_iau.281.1028114765','+DATA/DEMO/DATAFILE/HRPROD/portal_iau.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_mds.282.1028114767','+DATA/DEMO/DATAFILE/HRPROD/portal_mds.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_stb.283.1028114767','+DATA/DEMO/DATAFILE/HRPROD/portal_stb.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_wls.280.1028114765','+DATA/DEMO/DATAFILE/HRPROD/portal_wls.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_ias_opss.294.1028125227','+DATA/DEMO/DATAFILE/HRPROD/soa_ias_opss.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_ias_ums.289.1028125223','+DATA/DEMO/DATAFILE/HRPROD/soa_ias_ums.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_iau.293.1028125227','+DATA/DEMO/DATAFILE/HRPROD/soa_iau.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_mds.291.1028125225','+DATA/DEMO/DATAFILE/HRPROD/soa_mds.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_soainfra.295.1028125229','+DATA/DEMO/DATAFILE/HRPROD/soa_soainfra.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_stb.290.1028125225','+DATA/DEMO/DATAFILE/HRPROD/soa_stb.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/soa_wls.288.1028125223','+DATA/DEMO/DATAFILE/HRPROD/soa_wls.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/sysaux.275.1027852675','+DATA/DEMO/DATAFILE/HRPROD/sysaux.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/system.274.1027852675','+DATA/DEMO/DATAFILE/HRPROD/system.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/undo_2.277.1027852725','+DATA/DEMO/DATAFILE/HRPROD/undo_2.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/undotbs1.273.1027852675','+DATA/DEMO/DATAFILE/HRPROD/undotbs1.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/users.278.1027852727','+DATA/DEMO/DATAFILE/HRPROD/users.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/TEMPFILE/portal_ias_temp.287.1028114771','+DATA/DEMO/TEMPFILE/HRPROD/portal_ias_temp.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/TEMPFILE/soa_ias_temp.292.1028125225','+DATA/DEMO/TEMPFILE/HRPROD/soa_ias_temp.dbf',
'/home/oracle/app/oracle/oradata/HRPROD/TEMPFILE/temp.276.1027852677','+DATA/DEMO/TEMPFILE/HRPROD/temp.dbf');有几个地方需要注意：
- 必须换行，建议一个datafile一行，因为sql有大小限制，如果字符过大会报以下错误
SP2-0341:
line overflow during variable substitution (>3000 characters at line 1)- 必须列出所有的datafile，如果按照单机迁移的方式，会报以下错误
ERROR at line 1:
ORA-65180: duplicate file name encountered -
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/sysaux.275.1027852675- 必须把TEMPFILE文件也要带上，不然会报TEMPFILE文件无法匹配
ERROR at line 1:
ORA-65005: missing or invalid file name pattern for file -
/home/oracle/app/oracle/oradata/HRPROD/TEMPFILE/temp.276.1027852677临时文件可以通过查询dba_temp_files获取
SQL> select file_name from dba_temp_files;
FILE_NAME
--------------------------------------------------------------------------------
/home/oracle/app/oracle/oradata/HRPROD/TEMPFILE/portal_ias_temp.287.1028114771
/home/oracle/app/oracle/oradata/HRPROD/TEMPFILE/soa_ias_temp.292.1028125225
/home/oracle/app/oracle/oradata/HRPROD/TEMPFILE/temp.276.1027852677- 目标文件的后缀不能带上原数字，比如源文件是
undo_2.277.1027852725，目标文件不能带上后面的数字，可以为undo_2.dbf，不然会报以下错误
ERROR at line 1:
ORA-65169: error encountered while attempting to copy file
/home/oracle/app/oracle/oradata/HRPROD/DATAFILE/portal_stb.283.1028114767
ORA-19504: failed to create file
"+DATA/DEMO/DATAFILE/HRPROD/portal_stb.283.1028114767"
ORA-17502: ksfdcre:4 Failed to create file
+DATA/DEMO/DATAFILE/HRPROD/portal_stb.283.1028114767
ORA-15046: ASM file name
'+DATA/DEMO/DATAFILE/HRPROD/portal_stb.283.1028114767' is not in
single-file creation form如果提示以下信息说明clone成功，可以通过show pdbs命令查看pdb状态。
Pluggable database created.
SQL> show pdbs
CON_ID CON_NAME OPEN MODE RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED READ ONLY NO
3 HRPROD MOUNTED可以看到clone完的pdb状态为MOUNTED，需要将其打开
SQL> alter pluggable database HRPROD open;
SQL> show pdbs
CON_ID CON_NAME OPEN MODE RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED READ ONLY NO
6 HRPROD READ WRITE NO 如果状态是OPEN WRITE就是正常的。
连接
这次迁移完后，并没有配置额外的连接信息，客户端通过以下tns信息就能连上数据库
HRPROD =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = db-scan)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = HRPROD) # pdb名称
)
)碰到的问题
本次迁移碰到的问题较多，主要是clone时参考RAC迁单机导致一直无法clone成功，一步步试错最终执行成功，并且在迁移结束后service name发生了变化，花了很长时间解决连接的问题，至今也不知道为何迁移完service name发生了变化，如果有知道的原因，欢迎在评论区留言。