In Oracle 11gR2, there is a good new feature whereby we can backup the fast or flash recovery area to a disk location which could be a remote destination via a NFS attached file system.
In earlier releases, we could only backup the Flash Recovery Area to tape and not disk via RMAN.
Recovery from disk in most cases is significantly faster than recovery from a tape device especially when we have a very large tape library and the right tape needs to be located or maybe we have a case where all tape drives are already in use and we have to perform a critical database recovery at the same time.
The OSS or Oracle Suggested Strategy for backups involves a disk based backup method and level 0 datafile copies and subsequent leevl 1 incremental backupsets are all stored on local disk.
So what happens if we lose the local server and with it all our disk based backups? – we have to do a full database restore from tape which can be very time consuming.
The 11g RMAN command BACKUP RECOVERY AREA TO DESTINATION lets us specify a secondary backup location for all our backups which are stored in the Fast Recovery Area.
In this example we are backing up the FRA on a daily basis after the OSS backup to disk completes via the command:
backup recovery area to destination ‘/mnt/remote/backups/orasql/FRA_BACKUP/’
If we run a LIST BACKUP OF DATABASE we can see that there are two copies of the backupset #479. One stored in the FRA on the local server /u01 file system and one in the remote location which is a file server attached via NFS to the local server.
List of Backup Pieces for backup set 479 Copy #1
BP Key Pc# Status Piece Name
------- --- ----------- ----------
565 1 AVAILABLE /u01/app/oracle/flash_recovery_area/SQLFUN/backupset/2012_08_01/o1_mf_nnnd1_ORA_OEM_LEVEL_0_81jgs7qf_.bkp
Backup Set Copy #2 of backup set 479
Device Type Elapsed Time Completion Time Compressed Tag
----------- ------------ --------------- ---------- ---
DISK 00:00:18 01-AUG-12 NO ORA_OEM_LEVEL_0
List of Backup Pieces for backup set 479 Copy #2
BP Key Pc# Status Piece Name
------- --- ----------- ----------
571 1 AVAILABLE /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_08_01/o1_mf_nnnd1_ORA_OEM_LEVEL_0_81jh0x4l_.bkp
Let us now test a restore using this remote backup location by simulating a total server failure where we lose all our disk based backups residing on the local server which has crashed.
To simulate a total server crash I do the following:
Shutdown the database.
Rename the directory holding the data files of the database
Rename the spfile and init.ora file
Rename the FRA directory for the database so that RMAN cannot find the local backups in the FRA
When we perform the restore and recovery, RMAN finds that it cannot access the backups stored in the FRA (because we have renamed the directory).
It will now try and restore the copy of the FRA backups which was stored in the remote location.
This can be seen from the RMAN ouput like “reading from backup piece /mnt/remote/backups/orasql/FRA_BACKUP” ….
RESTORE SPFILE
RMAN> startup force nomount; startup failed: ORA-01078: failure in processing system parameters LRM-00109: could not open parameter file '/u01/app/oracle/product/11.2.0/dbhome_1/dbs/initsqlfun.ora' starting Oracle instance without parameter file for retrieval of spfile Oracle instance started Total System Global Area 158662656 bytes Fixed Size 2211448 bytes Variable Size 92275080 bytes Database Buffers 58720256 bytes Redo Buffers 5455872 bytes RMAN> restore spfile from '/mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_ncsnf_TAG20120528T080501_7w5oo92y_.bkp'; Starting restore at 28-MAY-12 using channel ORA_DISK_1 channel ORA_DISK_1: restoring spfile from AUTOBACKUP /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_ncsnf_TAG20120528T080501_7w5oo92y_.bkp channel ORA_DISK_1: SPFILE restore from AUTOBACKUP complete Finished restore at 28-MAY-12 RMAN> shutdown immediate; Oracle instance shut down RMAN> startup nomount; connected to target database (not started) Oracle instance started Total System Global Area 801701888 bytes Fixed Size 2217632 bytes Variable Size 490735968 bytes Database Buffers 301989888 bytes Redo Buffers 6758400 bytes
RESTORE CONTROFILE
RMAN> restore controlfile from '/mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_ncsnf_TAG20120528T080501_7w5oo92y_.bkp'; Starting restore at 28-MAY-12 allocated channel: ORA_DISK_1 channel ORA_DISK_1: SID=134 device type=DISK channel ORA_DISK_1: restoring control file channel ORA_DISK_1: restore complete, elapsed time: 00:00:01 output file name=/u01/app/oracle/oradata/sqlfun/control01.ctl output file name=/u01/app/oracle/flash_recovery_area/sqlfun/control02.ctl Finished restore at 28-MAY-12 RMAN> alter database mount; database mounted released channel: ORA_DISK_1
RESTORE DATABASE
RMAN> catalog start with '/mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN'; searching for all files that match the pattern /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN List of Files Unknown to the Database ===================================== File Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_annnn_TAG20120528T081134_7w5oob2y_.bkp File Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_annnn_TAG20120528T093614_7w5ongvb_.bkp File Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_ncsnf_TAG20120528T080501_7w5oo92y_.bkp File Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_nnndf_TAG20120528T080501_7w5onhys_.bkp Do you really want to catalog the above files (enter YES or NO)? YES cataloging files... cataloging done List of Cataloged Files ======================= File Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_annnn_TAG20120528T081134_7w5oob2y_.bkp File Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_annnn_TAG20120528T093614_7w5ongvb_.bkp File Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_ncsnf_TAG20120528T080501_7w5oo92y_.bkp File Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_nnndf_TAG20120528T080501_7w5onhys_.bkp RMAN> restore database; Starting restore at 28-MAY-12 using channel ORA_DISK_1 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 00001 to /u01/app/oracle/oradata/sqlfun/system01.dbf channel ORA_DISK_1: restoring datafile 00002 to /u01/app/oracle/oradata/sqlfun/sysaux01.dbf channel ORA_DISK_1: restoring datafile 00003 to /u01/app/oracle/oradata/sqlfun/undotbs01.dbf channel ORA_DISK_1: restoring datafile 00004 to /u01/app/oracle/oradata/sqlfun/users01.dbf channel ORA_DISK_1: restoring datafile 00005 to /u01/app/oracle/oradata/sqlfun/threatened_fauna_data.dbf channel ORA_DISK_1: reading from backup piece /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_nnndf_TAG20120528T080501_7w5onhys_.bkp channel ORA_DISK_1: piece handle=/mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_nnndf_TAG20120528T080501_7w5onhys_.bkp tag=TAG20120528T080501 channel ORA_DISK_1: restored backup piece 1 channel ORA_DISK_1: restore complete, elapsed time: 00:00:55 Finished restore at 28-MAY-12
RECOVER DATABASE
RMAN> list backup of archivelog all;
List of Backup Sets
===================
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
164 68.50K DISK 00:00:00 28-MAY-12
BP Key: 164 Status: AVAILABLE Compressed: NO Tag: TAG20120528T081134
Piece Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_annnn_TAG20120528T081134_7w5oob2y_.bkp
List of Archived Logs in backup set 164
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- --------- ---------- ---------
1 386 8176419 28-MAY-12 8176669 28-MAY-12
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ ---------------
165 68.50K DISK 00:00:00 28-MAY-12
BP Key: 165 Status: AVAILABLE Compressed: NO Tag: TAG20120528T093614
Piece Name: /mnt/remote/backups/orasql/FRA_BACKUP/SQLFUN/backupset/2012_05_28/o1_mf_annnn_TAG20120528T093614_7w5ongvb_.bkp
List of Archived Logs in backup set 165
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- --------- ---------- ---------
1 386 8176419 28-MAY-12 8176669 28-MAY-12
RMAN> recover database until sequence 387;
Starting recover at 28-MAY-12
using channel ORA_DISK_1
starting media recovery
media recovery complete, elapsed time: 00:00:01
Finished recover at 28-MAY-12
RMAN> alter database open resetlogs;
database opened