DupDBusingRMAN

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How I duplicate a database using RMAN

This document aims to describe the duplication of a database using RMAN in a windows

environment on Oracle 10g.

It's quite easy to backup and recover a database using RMAN. But RMAN can do morethan that.

For instance, it is possible to duplicate a database from one server to another.

I need this duplication ability because I got a database for training purpose. This database

must be fresh to train my users with the latest customers information, products etc but

also for the development team. However, its not possible to perform a cold backup

because my system is critical.

To help myself, I used this document:

http://download.oracle.com/docs/cd/B14117_01/server.101/b10734/toc.htm

The document above is really helpful but I've encountered some errors and had difficulties

to connect to the remote server. I'm also facing this task with a more practical eye than the

document.

Before starting, a little convention:

Values with [] are variables. It should be changed to fit others environment.

Im going to call the live dbs host PRIMARY and the duplicated databases host

AUXILIARY. Those are the terms used by RMAN.

To make things simple, I like to use the same server architecture on both servers. This willavoid the renaming of files.

Below is a list of things I will do:

1)On the PRIMARY host

Add the option UR=A in the CONNECT_DATA part of my tnsnames.ora entry toconnect to my auxiliary database. It should look like this:

AUXILIARY.WORLD =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (COMMUNITY = tcp.world)(PROTOCOL = TCP)(Host =

AUXILIARY)(PORT = MYDBPORT))

)

(CONNECT_DATA = (SERVICE_NAME = AUXILIARY.WORLD)(UR=A))

)

Perform a backup with RMAN:


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C:\>set oracle_sid= PRIMARYDB

C:\>rman target /

RMAN>backup database plus archivelog not backed up 1 times;

Move the backup folder from PRIMARY to AUXILIARY host. I would move it tothe same location as on the PRIMARY host.2) On the AUXILIARY host

RMAN does not recreate the folder structure as it is on production automatically, so it has

to be done manually. They are:

Datafiles folders Control files folders

Traces folder

Archives log folder pfile (I got a pfile folder where the SPFILE is located. Then in

oracle_home\database I got a file called initSID.ora and inside this file the

following line: SPFILE=[drive:\SPFILEpath\SPFILESID.ora]

The oracle service must be created on first hand. So, I copy the SPFILE from PRIMARY to

AUXILIARY and move it in the same location as on the PRIMARY server.

Then I create the service using oradim command:

It is possible to create a new password for the sys user. The use of -syspwd option as in this

example can do that. Otherwise, I would just copy the password file from PRIMARY. Its

located in [ORACLE_HOME]\database]

C:\>oradim -NEW -SID [as on PRIMARY] -syspwd acomplexepassword

-startmode auto

I would then create my listener using net services.

I will also need to create my tnsnames.ora and sqlnet.ora for this new database. I find it

more convenient to use implicit connection when logging in locally. To do so, I would add

the following in my sqlnet.ora:

SQLNET.AUTHENTICATION_SERVICES =(NTS,BEQ)

With the BEQ option, it is possible if logging in on windows with a user belonging to

ora_dba group, to connect locally without providing usernames and passwords.

When this is done it is possible to connect to the database with SQLplus and start the

database in nomount mode.


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C:\set oracle_sid=SameAsPRIMARY

C:\sqlplus / as sysdba(thats thanks to BEQ in sqlnet.ora)

SQL>startup nomount

If the database wont start with an error telling me its not finding the spfile, that means thatthe spfile is not located in [ORACLE_HOME]\database], or that it's not pointing to the

right folder.

In that case, it's still possible to start the database using the following command:

SQL>startup nomount spfile=[alternate_path\SPFILESID.ora]

3) Go back to PRIMARY

If everything has been prepared carefully, I will be able to connect to PRIMARY and

AUXILIARY with RMAN from PRIMARY.

C:\set oracle_sid=PRIMARY

C:\rman target / auxiliary sys/[email protected]

I'm connecting to PRIMARY without username and password but because I connect to

AUXILIARY remotely, username and password is required.

Then I run the following:

RMAN>run{

RMAN>ALLOCATE AUXILIARY CHANNEL aux1 DEVICE TYPE DISK;

RMAN>RMAN>ALLOCATE AUXILIARY CHANNEL aux2 DEVICE TYPE

DISK;RMAN>ALLOCATE AUXILIARY CHANNEL aux3 DEVICE TYPE DISK;

RMAN>DUPLICATE TARGET DATABASE TO SameAsPRIMARY

NOFILENAMECHECK UNTIL TIME 'sysdate -0.04';}

With this command I will allocate 3 auxiliary channels which will be used for the

duplication.

I use the same SID for AUXILIARY and for PRIMARY, so it's a bit scary and confusing

(hence the SameAsPRIMARY naming). Its reassuring to know that the duplication wont

work if the database is open. RMAN will just say that to run this command the database

must be in nomount mode and return an error. Plus the command will connect only toauxiliary (specified at connection time) using the tnsnames value used in the connection to

RMAN.

Since RMAN is using the production repository to duplicate the database, it will try to

recover the data with the latest archive logs created on production. But they have been

moved manually and not existing in the AUXILIARY environment. If RMAN could move

the archive logs continuously it would be a standby DB. So RMAN sends an error saying

that its not finding some archive logs.


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form the download of any content, materials, information or software.

To solve this problem, I will run the duplicate command with the UNTIL TIME option.

The best way Ive found is to specify UNTIL TIME sysdate - X.

sysdate -1 is one day before. The duplication would be one day old. 1/24 = 0.04 would be

one hour before current state of PRIMARY database.

RMAN will automatically open the database when he's done recovering it.

However, if for some reasons, archive logs were missing, the duplication process will stop.

But this doesn't mean that the duplication has failed. Only the last step, opening the

database did not happen.

So, it's possible to open the database manually. At this point, because of the recovery, the

database is already mounted. So we must run an alter database instead of a startup.

On the AUXILIARY host, I run the following command:

C:\>set oracle_sid= [sameasPRIMARY]

C:\>sqlplus / as sysdba

SQL> alter database open resetlogs;

The database is duplicated.

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