mardi 15 novembre 2011

Oracle 11g: Monitoring RMAN backups


If you are connected as SYSDBA

The following dynamic views give information about backups performance and statistics:

View Name Description
V$BACKUP_SETBackupset created
V$BACKUP_PIECEAll backup piece created
V$DATAFILE_COPYAll image copies created
V$BACKUP_FILESAll files created during backups
V$BACKUP_DATAFILEAll datafiles backuped and gives information about the moniroting of incremential backups


If you are connected as the catalog owner

View Name Description
RC_BACKUP_SETBackupset created
RC_BACKUP_PIECEAll backup piece created
RC_DATAFILE_COPYAll image copies created
RC_BACKUP_FILESAll files created during backups
RC_BACKUP_DATAFILEAll datafiles backuped and gives information about the moniroting of incremential backups

note: The following sql request gives information about the number of block read for an incremental level 1 backup.
sqlplus / as sysdba
SQL> select file#,
         avg(datafile_blocks),
         avg(blocks_read),
         avg(blocks_read/datafile_blocks) * 100 as PCT_READ_FOR_BACKUP,
         avg(blocks)
  from v$backup_datafile
  where used_change_tracking = 'YES'
        and incremental_level > 0
  group by file#;
Incremental level 1 backup are interesting as the value of the PCT_READ_FOR_BACKUP column is less than 50%. Above this value, it is recommanded to perform a level 0 incremential backup.