Aunque suele ser menos habitual tener que recuperar una base de datos en la misma máquina que en un host diferente, en esta entrada vamos a indicar los pasos necesarios para poder recuperar una base de datos en el mismo host, en este caso no estamos usando ASM como almacenamiento. La base de datos origen se llama «test» y nuestra copia se llamará «testcopy».

To do so, we start from a previously performed backup .

In our case we have launched the following:

RMAN> run {
allocate channel t1 type disk;
allocate channel t2 type disk;
allocate channel t3 type disk;
allocate channel t4 type disk;
backup format ‘/u01/backup/%U’ (base de datos);
backup format ‘/u01/backup/%U’ (archivelog all);
backup format ‘/u01/backup/%U’ current controlfile;
}

Before we begin, let's create the post the oratab of the new database.
We edit the oratab file and add the new database:

vi /etc/oratab

test:/u01/sw:N
testcopy:/u01/sw:N

El primer paso es copiar el pfile de la base de datos actual, en nuestro caso «test» con el que arrancaremos nuestra base de datos, basta con los mínimos parámetros necesarios. Un fichero init con los parámetros mínimos sería algo parecido a lo que muestro aquí posteriormente.
Muy importante fijarse en los parámetros «db_create_file_dest» donde indicamos donde se guardarán nuestros datos, en este escenario es muy importante, ya que estamos recuperando la base de datos en un mismo host donde tenemos nuestra base de datos origen, también es muy importante el parámetro «db_unique_name», que diferenciará nuestra copia de la original.

[oracle@localhost dbs]$ cat inittestcopy.ora
*.compatible=’19.0.0′
*.db_block_size=8192
*.db_create_file_dest=’/data/testcopy/’
*.db_name=’test’
*.db_unique_name=’testcopy’
*.diagnostic_dest=’/u01/app/oracle’
*.open_cursors=300
*.pga_aggregate_target=797m
*.processes=300
*.remote_login_passwordfile=’EXCLUSIVE’
*.sga_target=2388m
*.undo_tablespace=’UNDOTBS1′

We create the spfile of our new database through the pfile.

SQL> create spfile from pfile='inittestcopy.ora';
File created.

We check that the spfile has been created correctly:

SQL> startup nomount

ORACLE instance started.
Total System Global Area 2516581464 bytes
Fixed Size 8899672 bytes
Variable Size 536870912 bytes
Database Buffers 1962934272 bytes
Redo Buffers 7876608 bytes

SQL> show parameter pfile

NAME TYPE VALUE
————————————————
spfile string /u01/sw/dbs/spfiletestcopy.ora

We restore the controlfile:

Nos conectamos a RMAN y recuperamos el controlfile.
Nota. Podemos localizar el backup del controlfile, conectándonos a la base de datos «original», o base de datos a copiar, en nuestro caso test y ejecutar el siguiente comando.

RMAN> list backup of controlfile;

Once connected to the testcopy database, through rman, we retrieve the copy of the controlfile that we have located previously.

RMAN> restore controlfile from '/u01/backup/0e267imt_1_1';
Starting restore at 12-SEP-23
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=17 device type=DISK
channel ORA_DISK_1: restoring control file
channel ORA_DISK_1: restore complete, elapsed time: 00:00:03
output file name=/data/testcopy/TESTCOPY/controlfile/o1_mf_lj1qob64_.ctl
Finished restore at 12-SEP-23

We set up the database:

RMAN> alter database mount;
released channel: ORA_DISK_1
Statement processed

Before launching the database recovery, let's make sure that the redo log files are in the right path. This can be done with the following query:

 set lines 200
col member format a60
select a.thread#,a.group#,b.type,b.member,a.bytes/1048576
from v$log a,v$logfile b
where a.group#=b.group# order by a.group#;

If the redo logs point to the old database we have to change them to the location they will have in our new database. To do this we launch the following command:

SQL> alter database rename file ‘<old file location and name>’ to ‘<new location and name>’;

You can help yourself with a query like the following to do it automatically;

select ‘ALTER DATABASE RENAME FILE »’||member||»’ TO »<localización destino> ||substr(member,INSTR(member,’\’,-1,1),length(member)) ||»’;’ from v$logfile;

We execute the rename of the datafiles and we check it with the previously launched query to make sure that the change of location is correct:

ALTER DATABASE RENAME FILE ‘/data/test/TEST/onlinelog/o1_mf_3_hz8q3jd1_.log’ TO ‘/data/testcopy/TESTCOPY/redolog/o1_mf_3_hz8q3jd1_.log’;
ALTER DATABASE RENAME FILE ‘/u01/app/oracle/fast_recovery_area/TEST/onlinelog/o1_mf_3_hz8q4lbd_.log’ TO ‘/data/testcopy/TESTCOPY/redolog/o1_mf_3_hz8q4lbd_.log’;
ALTER DATABASE RENAME FILE ‘/data/test/TEST/onlinelog/o1_mf_2_hz8q3jcc_.log’ TO ‘/data/testcopy/TESTCOPY/redolog/o1_mf_2_hz8q3jcc_.log’;
ALTER DATABASE RENAME FILE ‘/u01/app/oracle/fast_recovery_area/TEST/onlinelog/o1_mf_2_hz8q4qgp_.log’ TO ‘/data/testcopy/TESTCOPY/redolog/o1_mf_2_hz8q4qgp_.log’;
ALTER DATABASE RENAME FILE ‘/data/test/TEST/onlinelog/o1_mf_1_hz8q3jbo_.log’ TO ‘/data/testcopy/TESTCOPY/redolog/o1_mf_1_hz8q3jbo_.log’;
ALTER DATABASE RENAME FILE ‘/u01/app/oracle/fast_recovery_area/TEST/onlinelog/o1_mf_1_hz8q4lfp_.log’ TO ‘/data/testcopy/TESTCOPY/redolog/o1_mf_1_hz8q4lfp_.log’;

SQL> set lines 200
col member format a60
select a.thread#,a.group#,b.type,b.member,a.bytes/1048576
from v$log a,v$logfile b
where a.group#=b.group# order by a.group#;SQL> SQL> 2 3
THREAD# GROUP# TYPE MEMBER A.BYTES/1048576

1 1 ONLINE /data/testcopy/TESTCOPY/redolog/o1_mf_1_hz8q4lfp_.log

---

We restore the database through the RMAN backup.

With the target database (testcopy) mounted, we launch the following command:

run{
set newname for database to ‘/data/tescopy/TESCOPY/%U’;
RESTORE DATABASE;
SWITCH DATAFILE ALL;
RECOVER DATABASE;
}

The command "set newname for database to", indicates where we want our files of our new DB to be stored, this can be done manually, renaming each datafile or in the way exposed in this document.

If everything is correct, you will have an output similar to this one:

Starting restore at 13-SEP-23
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=237 device type=DISK
channel ORA_DISK_1: starting datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_DISK_1: restoring datafile 00004 to /data/tescopy/TESCOPY
.

starting media recovery
archived log for thread 1 with sequence 23 is already on disk as file /u01/app/oracle/fast_recovery_area/TEST/archivelog/2023_09_12/o1_mf_1_23_lj1pkgkj_.arc
archived log file name=/u01/app/oracle/fast_recovery_area/TEST/archivelog/2023_09_12/o1_mf_1_23_lj1pkgkj_.arc thread=1 sequence=23
unable to find archived log
archived log thread=1 sequence=24
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 09/13/2023 13:15:18
RMAN-06054: media recovery requesting unknown archived log for thread 1 with sequence 24 and starting SCN of 313766

This output indicates that the database has been successfully retrieved and that the latest available archive has been applied.
At this point we can open our database.

SQL> alter database open resetlogs;
Database altered.

We check that everything is correct:

SQL> select name from v$datafile;

/data/tescopy/TESCOPY/data_D-TEST_TS-SYSTEM_FNO-1
/data/tescopy/TESCOPY/data_D-TEST_TS-SYSAUX_FNO-3
/data/tescopy/TESCOPY/data_D-TEST_TS-UNDOTBS1_FNO-4
/data/tescopy/TESCOPY/data_D-TEST_TS-USERS_FNO-7

SQL> Select member from v$logfile;

/data/testcopy/TESTCOPY/onlinelog/o1_mf_3_lj37cp5g_.log
/data/testcopy/TESTCOPY/onlinelog/o1_mf_2_lj37cp4r_.log
/data/testcopy/TESTCOPY/onlinelog/o1_mf_1_lj37cp41_.log

En este último punto, ya tendríamos la base de datos recuperada, en este caso puede ser interesante cambiar renombrar la base de datos, ya que el DBID y el DB_NAME de la base de datos original y la copia será el mismo. Para ello recomiendo realizarlo con la herramienta NID, mejor que de forma manual.