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Category :
Database
Resources -> Backup and Recovery
DB Version
:
Oracle 9i
OS Details :
Sun Solaris9
One
of the new features introduced in 9i with the recovery mechanism is
the availability of block-level recovery. Block Media Recovery (BMR)
has been introduced in 9i which improves database availability and
also greatly reduces the mean time to recover (MTTR).
Block Media Recovery (BMR) is an
option that's available only with the use of RMAN and helps us to
recover from errors like these:
ORA-01578: ORACLE data
block corrupted (file # 118, block # 8)
ORA-01110: data file
118: '/ora9idata/tables/project_tbs01.dbf'
Prior to version 9i, an error
like the one above would mean a recovery of datafile 118, making all
the objects within that file unavailable until the recovery has been
completed. Using RMAN in 9i, you can recover a single block or
multiple blocks within a single file or blocks across multiple files.
The following block level recovery options are available with RMAN in
9i:
The following RMAN command helps
recover a single block from a datafile:
BLOCKRECOVER DATAFILE 118
BLOCK 8;
The following RMAN command helps
recover multiple block from a datafile:
BLOCKRECOVER DATAFILE 118
BLOCK 8,16,24;
The following RMAN command helps
recover blocks across multiple datafiles:
BLOCKRECOVER DATAFILE 118
BLOCK 8 DATAFILE 220 BLOCK 99;
Block Media Recovery (BMR)
applies only to complete database recovery. Incomplete recovery is not
possible since a single datafile or part of the database cannot be set
to be recovered to a different point in time.
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