"Recovery Continuity" should be a critical part of your Oracle Database support plan.
As multitenant Oracle Databases becomes the standard for database implementations, you need to ensure that you maintain your recovery window even as your pluggable moves around your environment.
Above is the recommended practice we have all been hearing about to make upgrades of your Oracle Database easier. Unplug from your current CDB (CDBPROD122) plug into a new CDB (CDB19C) that has the new release. What you need to think about however, is how am I going to ensure that I can recover my pluggable database to any point in time, all the way this migration without a huge amount of downtime?
Above is the recommended practice we have all been hearing about to make upgrades of your Oracle Database easier. Unplug from your current CDB (CDBPROD122) plug into a new CDB (CDB19C) that has the new release. What you need to think about however, is how am I going to ensure that I can recover my pluggable database to any point in time, all the way this migration without a huge amount of downtime?
This is where preplugin backups, and some planning comes into play.
You can find out more about preplugin backups with some of the links below.
- Preplugin Backups
(Doc ID 2358523.1)
Let's take a look at what I am doing for my pluggable database PDBDWPROD before I migrate it from OLDCDB to NEWCDB.
Pre-unplug
In the picture PDBDWPROD is plugged into CDBPROD122.
In my environment I am testing my PDB (PDBDWPROD) and it is plugged into OLDCDB, migrating to NEWCDB.
To ensure that I have a good restore point I am going to perform a full backup of my pluggable database prior to unplugging, and I will also include an archive log backups.
RMAN> backup incremental level 0 pluggable database PDBDWPROD plus archivelog delete input;
Starting backup at 15-APR-22
current log archived
allocated channel: ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: SID=426 device type=SBT_TAPE
channel ORA_SBT_TAPE_1: Oracle Database Backup Service Library VER=23.0.0.1
channel ORA_SBT_TAPE_1: starting compressed archived log backup set
channel ORA_SBT_TAPE_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=185 RECID=186 STAMP=1102096068
input archived log thread=1 sequence=186 RECID=187 STAMP=1102096071
input archived log thread=1 sequence=187 RECID=188 STAMP=1102096147
input archived log thread=1 sequence=188 RECID=189 STAMP=1102096166
input archived log thread=1 sequence=189 RECID=190 STAMP=1102096288
channel ORA_SBT_TAPE_1: starting piece 1 at 15-APR-22
channel ORA_SBT_TAPE_1: finished piece 1 at 15-APR-22
piece handle=6l0r19t1_213_1_1 tag=TAG20220415T175129 comment=API Version 2.0,MMS Version 23.0.0.1
channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:03
channel ORA_SBT_TAPE_1: deleting archived log(s)
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_185_k5mcy4w8_.arc RECID=186 STAMP=1102096068
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_186_k5mcy7xv_.arc RECID=187 STAMP=1102096071
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_187_k5md0m8l_.arc RECID=188 STAMP=1102096147
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_188_k5md16rt_.arc RECID=189 STAMP=1102096166
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_189_k5md50qy_.arc RECID=190 STAMP=1102096288
Finished backup at 15-APR-22
Starting backup at 15-APR-22
using channel ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: starting compressed incremental level 0 datafile backup set
channel ORA_SBT_TAPE_1: specifying datafile(s) in backup set
input datafile file number=00066 name=/u01/app/oracle/oradata/OLDCDB/PDBDWPROD/sysaux01.dbf
input datafile file number=00065 name=/u01/app/oracle/oradata/OLDCDB/PDBDWPROD/system01.dbf
input datafile file number=00068 name=/u01/app/oracle/oradata/OLDCDB/PDBDWPROD/PDBDWPROD.dbf
input datafile file number=00067 name=/u01/app/oracle/oradata/OLDCDB/PDBDWPROD/undotbs01.dbf
channel ORA_SBT_TAPE_1: starting piece 1 at 15-APR-22
channel ORA_SBT_TAPE_1: finished piece 1 at 15-APR-22
piece handle=6m0r19t5_214_1_1 tag=TAG20220415T175132 comment=API Version 2.0,MMS Version 23.0.0.1
channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:15
Finished backup at 15-APR-22
Starting backup at 15-APR-22
current log archived
using channel ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: starting compressed archived log backup set
channel ORA_SBT_TAPE_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=190 RECID=191 STAMP=1102096309
channel ORA_SBT_TAPE_1: starting piece 1 at 15-APR-22
channel ORA_SBT_TAPE_1: finished piece 1 at 15-APR-22
piece handle=6n0r19tm_215_1_1 tag=TAG20220415T175150 comment=API Version 2.0,MMS Version 23.0.0.1
channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:03
channel ORA_SBT_TAPE_1: deleting archived log(s)
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_190_k5md5osn_.arc RECID=191 STAMP=1102096309
Finished backup at 15-APR-22
Starting Control File and SPFILE Autobackup at 15-APR-22
piece handle=c-1180802953-20220415-07 comment=API Version 2.0,MMS Version 23.0.0.1
Finished Control File and SPFILE Autobackup at 15-APR-22
RMAN>
Then right before the unplug I am going to execute another archive log backup, immediately followed by the unplug.
RMAN> backup archivelog all delete input;
Starting backup at 15-APR-22
current log archived
allocated channel: ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: SID=442 device type=SBT_TAPE
channel ORA_SBT_TAPE_1: Oracle Database Backup Service Library VER=23.0.0.1
channel ORA_SBT_TAPE_1: starting compressed archived log backup set
channel ORA_SBT_TAPE_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=191 RECID=192 STAMP=1102096412
input archived log thread=1 sequence=192 RECID=193 STAMP=1102096418
input archived log thread=1 sequence=193 RECID=194 STAMP=1102096424
input archived log thread=1 sequence=194 RECID=195 STAMP=1102096502
channel ORA_SBT_TAPE_1: starting piece 1 at 15-APR-22
channel ORA_SBT_TAPE_1: finished piece 1 at 15-APR-22
piece handle=6p0r1a3n_217_1_1 tag=TAG20220415T175503 comment=API Version 2.0,MMS Version 23.0.0.1
channel ORA_SBT_TAPE_1: backup set complete, elapsed time: 00:00:07
channel ORA_SBT_TAPE_1: deleting archived log(s)
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_191_k5md8w57_.arc RECID=192 STAMP=1102096412
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_192_k5md926n_.arc RECID=193 STAMP=1102096418
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_193_k5md9893_.arc RECID=194 STAMP=1102096424
archived log file name=/u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_194_k5mdcpko_.arc RECID=195 STAMP=1102096502
Finished backup at 15-APR-22
Starting Control File and SPFILE Autobackup at 15-APR-22
piece handle=c-1180802953-20220415-08 comment=API Version 2.0,MMS Version 23.0.0.1
Finished Control File and SPFILE Autobackup at 15-APR-22
Then the unplug
SQL> alter pluggable database PDBDWPROD close immediate;
Pluggable database altered.
SQL> ALTER PLUGGABLE DATABASE PDBDWPROD UNPLUG INTO '/tmp/PDBDWPROD.xml';
Pluggable database altered.
SQL>
Plug
SQL> create pluggable database PDBDWPROD using '/tmp/PDBDWPROD.xml' nocopy tempfile reuse KEYSTORE IDENTIFIED BY "change-on-install" ;
Pluggable database created.
SQL> alter pluggable database PDBDWPROD open;
Pluggable database altered.
Update database and set restore point
Now I am going create some objects in my PDB, set a restore point, and then create a few more objects to ensure I am restoring to a point in time.
SQL> alter session set container=PDBDWPROD;
Session altered.
SQL> create table bgrenn.postmove as select * from dba_objects ;
Table created.
############################ perform a couple of log switches
SQL> alter session set container=CDB$ROOT;
Session altered.
SQL> alter system archive log current;
System altered.
SQL> alter system archive log current;
System altered.
SQL> alter session set container=PDBDWPROD;
Session altered.
############################ create a restore point
SQL> create restore point PDBDWPROD_restore;
Restore point created.
############################ create a second table
SQL> create table bgrenn.postrestorepoint as select * from dba_objects ;
Table created.
############################ perform a couple of log switches
SQL> alter session set container=CDB$ROOT;
Session altered.
SQL> alter system archive log current;
System altered.
SQL> alter system archive log current;
System altered.
SQL> alter system archive log current;
System altered.
Backups available post plugin
Now using the preplugin commands I can see the backups that we taken before the migration.
rman> SET PREPLUGIN CONTAINER=PDBDWPROD;rman> list preplugin backup of pluggable database PDBDWPROD;
RMAN> list preplugin backup of pluggable database PDBDWPROD;
starting full resync of recovery catalog
full resync complete
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
209 Incr 0 284.50M SBT_TAPE 00:00:07 15-APR-22
BP Key: 209 Status: AVAILABLE Compressed: YES Tag: TAG20220415T175132
Handle: 6m0r19t5_214_1_1 Media: objectstorage.us-ashburn-1.oraclecloud.com/n/xxx/oldcdb
List of Datafiles in backup set 209
Container ID: 5, PDB Name: PDBDWPROD
File LV Type Ckp SCN Ckp Time Abs Fuz SCN Sparse Name
---- -- ---- ---------- --------- ----------- ------ ----
59 0 Incr 6346380 15-APR-22 NO /u01/app/oracle/oradata/OLDCDB/PDBDWPROD/system01.dbf
60 0 Incr 6346380 15-APR-22 NO /u01/app/oracle/oradata/OLDCDB/PDBDWPROD/sysaux01.dbf
61 0 Incr 6346380 15-APR-22 NO /u01/app/oracle/oradata/OLDCDB/PDBDWPROD/undotbs01.dbf
62 0 Incr 6346380 15-APR-22 NO /u01/app/oracle/oradata/OLDCDB/PDBDWPROD/PDBDWPROD.dbf
list preplugin backup of archivelog all;
List of Backup Sets
===================
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
208 2.25M SBT_TAPE 00:00:01 15-APR-22
BP Key: 208 Status: AVAILABLE Compressed: YES Tag: TAG20220415T175129
Handle: 6l0r19t1_213_1_1 Media: objectstorage.us-ashburn-1.oraclecloud.com/n/xxx/oldcdb
List of Archived Logs in backup set 208
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- --------- ---------- ---------
1 185 6345022 15-APR-22 6345387 15-APR-22
1 186 6345387 15-APR-22 6345399 15-APR-22
1 187 6345399 15-APR-22 6345803 15-APR-22
1 188 6345803 15-APR-22 6345912 15-APR-22
1 189 6345912 15-APR-22 6346322 15-APR-22
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
210 256.00K SBT_TAPE 00:00:00 15-APR-22
BP Key: 210 Status: AVAILABLE Compressed: YES Tag: TAG20220415T175150
Handle: 6n0r19tm_215_1_1 Media: objectstorage.us-ashburn-1.oraclecloud.com/n/xxx/oldcdb
List of Archived Logs in backup set 210
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- --------- ---------- ---------
1 190 6346322 15-APR-22 6346391 15-APR-22
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
212 512.00K SBT_TAPE 00:00:02 15-APR-22
BP Key: 212 Status: AVAILABLE Compressed: YES Tag: TAG20220415T175503
Handle: 6p0r1a3n_217_1_1 Media: objectstorage.us-ashburn-1.oraclecloud.com/n/id20skavsofo/oldcdb
List of Archived Logs in backup set 212
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- --------- ---------- ---------
1 191 6346391 15-APR-22 6346585 15-APR-22
1 192 6346585 15-APR-22 6346593 15-APR-22
1 193 6346593 15-APR-22 6346601 15-APR-22
1 194 6346601 15-APR-22 6346663 15-APR-22
Restore from preplugin
I shutdown my pluggable database and start with "from preplugin" in the command in my rman session.
RAMN> alter pluggable database PDBDWPROD close;
RMAN> restore pluggable database PDBDWPROD from preplugin;
RMAN> alter pluggable database PDBDWPROD close;
Statement processed
starting full resync of recovery catalog
full resync complete
RMAN> restore pluggable database PDBDWPROD from preplugin;
Starting restore at 15-APR-22
using channel ORA_SBT_TAPE_1
using channel ORA_DISK_1
channel ORA_SBT_TAPE_1: starting datafile backup set restore
channel ORA_SBT_TAPE_1: specifying datafile(s) to restore from backup set
channel ORA_SBT_TAPE_1: restoring datafile 00059 to /u01/app/oracle/oradata/OLDCDB/PDBDWPROD/system01.dbf
channel ORA_SBT_TAPE_1: restoring datafile 00060 to /u01/app/oracle/oradata/OLDCDB/PDBDWPROD/sysaux01.dbf
channel ORA_SBT_TAPE_1: restoring datafile 00061 to /u01/app/oracle/oradata/OLDCDB/PDBDWPROD/undotbs01.dbf
channel ORA_SBT_TAPE_1: restoring datafile 00062 to /u01/app/oracle/oradata/OLDCDB/PDBDWPROD/PDBDWPROD.dbf
channel ORA_SBT_TAPE_1: reading from backup piece 6m0r19t5_214_1_1
channel ORA_SBT_TAPE_1: piece handle=6m0r19t5_214_1_1 tag=TAG20220415T175132
channel ORA_SBT_TAPE_1: restored backup piece 1
channel ORA_SBT_TAPE_1: restore complete, elapsed time: 00:00:25
Finished restore at 15-APR-22
Recover from preplugin
Now I am running the recover from preplugin
recover pluggable database PDBDWPROD from preplugin;
RMAN>
Starting recover at 15-APR-22
using channel ORA_SBT_TAPE_1
using channel ORA_DISK_1
starting media recovery
channel ORA_SBT_TAPE_1: starting archived log restore to default destination
channel ORA_SBT_TAPE_1: restoring archived log
archived log thread=1 sequence=190
channel ORA_SBT_TAPE_1: reading from backup piece 6n0r19tm_215_1_1
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 04/15/2022 18:23:58
ORA-19870: error while restoring backup piece 6n0r19tm_215_1_1
ORA-19827: Restoring preplugin files to a recovery area is not supported.
RMAN>
You can see that it is not going to let me apply the archive logs by restoring them from backup to the local recovery area of my new CDB.
I need to catalog the archive logs themselves by restoring them.
By looking at the backup piece name, I can see it is looking for "sequence 190" and I restored it from my original CDB.
RMAN> restore archivelog sequence 190;
Starting restore at 15-APR-22
starting full resync of recovery catalog
full resync complete
allocated channel: ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: SID=449 device type=SBT_TAPE
channel ORA_SBT_TAPE_1: Oracle Database Backup Service Library VER=23.0.0.1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=71 device type=DISK
channel ORA_SBT_TAPE_1: starting archived log restore to default destination
channel ORA_SBT_TAPE_1: restoring archived log
archived log thread=1 sequence=190
channel ORA_SBT_TAPE_1: reading from backup piece 6n0r19tm_215_1_1
channel ORA_SBT_TAPE_1: piece handle=6n0r19tm_215_1_1 tag=TAG20220415T175150
channel ORA_SBT_TAPE_1: restored backup piece 1
channel ORA_SBT_TAPE_1: restore complete, elapsed time: 00:00:01
Finished restore at 15-APR-22
RMAN> list archivelog sequence 190;
List of Archived Log Copies for database with db_unique_name OLDCDB
=====================================================================
Key Thrd Seq S Low Time
------- ---- ------- - ---------
8134 1 190 A 15-APR-22
Name: /u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_190_k5mgd1h2_.arc
Now I need to catalog it in preplugin backup to continue the recovery.
I am able to copy the restored archive log to /tmp and catalog it, but I am still missing some pieces. I will continue restoring the rest of archivelogs that in the listing up to sequence 194
RMAN> restore archivelog sequence 190;
Starting restore at 15-APR-22
starting full resync of recovery catalog
full resync complete
allocated channel: ORA_SBT_TAPE_1
channel ORA_SBT_TAPE_1: SID=449 device type=SBT_TAPE
channel ORA_SBT_TAPE_1: Oracle Database Backup Service Library VER=23.0.0.1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=71 device type=DISK
channel ORA_SBT_TAPE_1: starting archived log restore to default destination
channel ORA_SBT_TAPE_1: restoring archived log
archived log thread=1 sequence=190
channel ORA_SBT_TAPE_1: reading from backup piece 6n0r19tm_215_1_1
channel ORA_SBT_TAPE_1: piece handle=6n0r19tm_215_1_1 tag=TAG20220415T175150
channel ORA_SBT_TAPE_1: restored backup piece 1
channel ORA_SBT_TAPE_1: restore complete, elapsed time: 00:00:01
Finished restore at 15-APR-22
RMAN> list archivelog sequence 190;
List of Archived Log Copies for database with db_unique_name OLDCDB
=====================================================================
Key Thrd Seq S Low Time
------- ---- ------- - ---------
8134 1 190 A 15-APR-22
Name: /u01/app/oracle/fast_recovery_area/OLDCDB/archivelog/2022_04_15/o1_mf_1_190_k5mgd1h2_.arc
Now that I restored and catalog all the backup pieces up to sequence 194, I will continue the recovery.
RMAN> recover pluggable database PDBDWPROD from preplugin;
Starting recover at 15-APR-22
using channel ORA_SBT_TAPE_1
using channel ORA_DISK_1
starting media recovery
archived log for thread 1 with sequence 191 is already on disk as file /tmp/o1_mf_1_191_k5mgw2fr_.arc
archived log for thread 1 with sequence 192 is already on disk as file /tmp/o1_mf_1_192_k5mgw83q_.arc
archived log for thread 1 with sequence 193 is already on disk as file /tmp/o1_mf_1_193_k5mgwlf8_.arc
archived log for thread 1 with sequence 194 is already on disk as file /tmp/o1_mf_1_194_k5mgx0t1_.arc
unable to find archived log
archived log thread=1 sequence=195
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 04/15/2022 18:40:31
RMAN-06054: media recovery requesting unknown archived log for thread 1 with sequence 195 and starting SCN of 6346663
I am finding that there is still one last archivelog (hopefully). This was the redo log that was active while I unplugged my database.
In fact I can see on the source CDB, that it is still the active redo log, so I am going to have to do a log switch to grab a copy of the archive log and catalog it.
SQL> select sequence#,status from v$log;
SEQUENCE# STATUS
---------- ----------------
195 CURRENT
193 INACTIVE
194 INACTIVE
Now that I have the last archive log, my preplug recovery is completed to the time it was unplugged.
RMAN> recover pluggable database PDBDWPROD from preplugin;
Starting recover at 15-APR-22
using channel ORA_SBT_TAPE_1
using channel ORA_DISK_1
starting media recovery
archived log for thread 1 with sequence 195 is already on disk as file /tmp/o1_mf_1_195_k5mhf79h_.arc
media recovery complete, elapsed time: 00:00:01
Finished recover at 15-APR-22
Recover post plugin
Now I can recover to my restore point, and open it up.
RMAN>
RMAN> recover pluggable database PDBDWPROD until restore point PDBDWPROD_restore;
Starting recover at 15-APR-22
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=4 device type=DISK
starting media recovery
archived log for thread 1 with sequence 101 is already on disk as file /u01/app/oracle/fast_recovery_area/NEWCDB/archivelog/2022_04_15/o1_mf_1_101_k5mf0rr5_.arc
archived log for thread 1 with sequence 102 is already on disk as file /u01/app/oracle/fast_recovery_area/NEWCDB/archivelog/2022_04_15/o1_mf_1_102_k5mf0s8b_.arc
archived log for thread 1 with sequence 103 is already on disk as file /u01/app/oracle/fast_recovery_area/NEWCDB/archivelog/2022_04_15/o1_mf_1_103_k5mf1wof_.arc
archived log for thread 1 with sequence 104 is already on disk as file /u01/app/oracle/fast_recovery_area/NEWCDB/archivelog/2022_04_15/o1_mf_1_104_k5mf1zqm_.arc
archived log for thread 1 with sequence 105 is already on disk as file /u01/app/oracle/fast_recovery_area/NEWCDB/archivelog/2022_04_15/o1_mf_1_105_k5mf22sk_.arc
archived log for thread 1 with sequence 106 is already on disk as file /u01/app/oracle/fast_recovery_area/NEWCDB/archivelog/2022_04_15/o1_mf_1_106_k5mf91fn_.arc
archived log for thread 1 with sequence 107 is already on disk as file /u01/app/oracle/fast_recovery_area/NEWCDB/archivelog/2022_04_15/o1_mf_1_107_k5mf94g2_.arc
archived log for thread 1 with sequence 108 is already on disk as file /u01/app/oracle/fast_recovery_area/NEWCDB/archivelog/2022_04_15/o1_mf_1_108_k5mf9wk2_.arc
media recovery complete, elapsed time: 00:00:01
Finished recover at 15-APR-22
RMAN> alter pluggable database PDBDWPROD open resetlogs;
Statement processed
starting full resync of recovery catalog
full resync complete
And let's make sure I can see that it was recovered until prior to my restore point, and that I can see the data in the table.
SQL> alter session set container=PDBDWPROD;
Session altered.
SQL> select table_name from dba_tables where owner='BGRENN';
TABLE_NAME
--------------------------------------------------------------------------------
POSTMOVE
SQL> select count(1) from bgrenn.postmove;
COUNT(1)
----------
73610
Conclusion :
Preplugin backups provide you with Recovery Continuity ensuring you can recovery your pluggable after migrating to a new PDB even before you take your first backup. As you can tell by my example, you want to make sure you take the backup as close to the point in time you are unplugging as possible to lessen the work to catalog and apply the archive logs. I would also recommend you take a backup on the new CDB as soon as possible.
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