Recovery Continuity with Multitenant

 Recovery Continuity with Multitenant is something you need to understand as you migrate databases from one CDB to another

Above is from a presentation that I recently gave to my internal Oracle Team. This was such a big hit (and very eye opening) that I wanted to make sure I share the information on my Blog

The first thing to point out is that before we (Oracle) moved to the multitenant architecture, life was simple. Below is my slide showing how databases were moving around as they upgraded.  Regardless of whether it was an out-of-place upgrade, or migrating it to a different host, the DB name stays, and the backups stay contiguous.

But, like many things in life, new ideas came along that changed the way we do things.  Multitenant is one of those things.  Don't get me wrong, multitenant is a great feature giving DBAs a lot more flexibility.  Below are a couple of pictures that show all the wonderful things that multitenant can do.

Above are the 2 slides from my presentation.  These slides are often used to show the benefits of multitenant.  I did point out on the last slide encryption keys that are used to secure the database with TDE.

The use of Encryption keys is an important point to think about.  With Multitenant (if you think about how it works), the CDB has a different encryption key from the PDB.  If I create an encrypted backup of my CDB, it is encrypted with the CDB key. The backup (and actual datafiles) for my PDB are encrypted with the PDB key.

Below is the next slide I used.  All the information on multitenant talks about how easy it is to unplug/plug (which it is), but ensuring you maintain your recovery window is the hard part.

Database backup and recovery in a multitenant environment

Here are some things to keep in mind in a multitenant environment

• Pluggable database backup pieces are ALWAYS kept independent of the CDB and other PDBs.  Even with a filesperset=1000 channels=1 each PDB, and the CDB will be individual backupsets.

• Pluggable databases can be backed up independently of each other, and of the CDB. “backup pluggable database xxx.

• You can perform a point in time recovery of a pluggable database independent of other PDBS. This requires local undo. “recover pluggable database until”

• Recovering a pluggable database requires a backup of the CDB (for metadata), and backups of the archive logs.

• All redo transactions for all PDBs are intertwined into a single redo stream. This will not change in the near future. 

• Flashback can be set at the PDB level

• You can create restore points within a PDB

When backing up a Multitenant environment, the item to keep in mind is that the RMAN catalog information is stored at the CDB level.  Pluggable databases are part of the CDB, and registration is done at the CDB.

The next image shows what a recovery of the Pluggable database looks like. Keep in mind that the datafiles for the  pluggable database get restored using the pluggable database backup, but to defuzzy them, the archive logs get restored from the CDB.  Remember that in a multitenant environment the redo/archive logs are intertwined at the CDB level.

The next image shows what is typically done to perform a PDB upgrade with unplug/plug. The pluggable database is migrated from 12c to 19c.

Now that the database is migrated, let's look at what happens to the RMAN catalog after the migration to ensure that we have a backup of the pluggable database.

• 

You can see in the image above, that the pluggable database is now associated with the CDB that the pluggable database is plugged into.

Now to go back to the image at the beginning of this post, you can see what it takes to restore and recovery the database throughout it's lifecycle.

• Backups that were taken through previous CDBs (for example an archival backup) needs to be restored through the CDB is was backed up through.
• Backups that were taken in original CDB can only be restored back to the original CDB.
• Pre-plugin backups provide a gateway between plugging in and when the first backup is taken
• Backups to the new CDB will restored back to the new CDB.

Finally some parting thoughts on backups of pluggable databases when migrating.

• Perform a full backup if possible (ZDLRA makes this easy) with the PDB mounted prior to unplugging. This is the best possible restore point after migrating.

• Keep the RMAN catalog entries for the old CDB as long as there are valid backups pieces. This could be years for keep backups.

• NOTE – On the ZDLRA you can execute “Pause Database” this will remove all backups, but leave the RMAN catalog entries.

• Ensure you have the encryption keys for both CDBs and PDBs for the needed recovery window which may be years.

• Keep track of CDB backups, as a PDB might be migrated between multiple CDBs throughout it’s backup cycle.

• NEVER delete a CDB backup that has needed backups

• NEVER delete any TDE keys or wallets that support needed backups.

Recovery Continuity of your Oracle Database

"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?

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)
• RMAN preplugin backups (docs)

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.