Q&As: Cold database backups

(Q) Which statements about Closed (cold/offline) database backups are correct?

  • ( ) You CAN perform closed database backups using RMAN.
  • ( ) To perform closed db backups with RMAN, the instance MUST be MOUNTED
  • ( ) You CAN perform user-managed closed database backups (OFFLINE backups), following the steps below:
    • Run shell script to collect location of all datafiles, control files, redo log files, and parameter files
    • If using server parameter file, run command to backup spfile
    • Shutdown the database normal or immediate
    • Run OS script to copy all datafiles, control files, redo logs and parameter files to backup area
    • Startup the database
  • ( ) You CANNOT run a Data Pump Export on a closed database.

Q&As: Block Media Recovery

(Q) What is Block Media Recovery?

Recovery of specified blocks within a data file
Leaves the affected datafiles ONLINE and recovers only the damaged/corrupted data blocks.

$ rman
RMAN> connect target /
connected to target database: ORCL11G (DBID=123456789)

RMAN> recover datafile 2 block 13;

RMAN> recover … 
        From backupset …
        Exclude flashback log

     (To recover ALL blocks logged in V$DATABASE_BLOCK_CORRUPTION)
RMAN> recover corruption list;

Q&As: Fast Recovery Area (II)

(Q) What initialization parameters are used to configure a Fast Recovery Area?

  • DB_RECOVERY_FILE_DEST - specifies default location for fast recovery area.
  • DB_RECOVERY_FILE_DEST_SIZE - specifies (in bytes) the hard limit on the total space to be used by target database recovery files created in the fast recovery area
  • (optional) DB_FLASHBACK_RETENTION_TARGET -Specifies the upper limit (minutes) on how far back in time the database may be flashed back.

(Q) Can you configure the Fast Recovery Area on an ASM disk group?

  • Yes

(Q) How large should you configure the Fast Recovery Area?

  • At an ABSOLUTE MINIMUM, it should be large enough to containt the archived redo logs not yet on tape.
  • Scenario:
    • If you use incrementally updated backups and set the backup retention policy to REDUNDANCY 1, you can determine the size of the fast recovery area as below: