Oracle Database 11 g - Online Public Access Catalog

86 CHAPTER 2 ■ DATABASE DIAGNOSABILITY AND FAILURE REPAIRFigure 2-4. The Checkers subpage in Database ControlManual Checks with the RMAN Validate CommandIn previous releases of the Oracle Database, you could use the backup ... validate commandto validate your backups. Essentially, what this command helped you do was check for bothlogical and physical intrablock corruption in the datafiles and also whether the datafiles couldbe backed up by RMAN. The command doesn’t actually perform the actual backup but onlyvalidates the datafiles so you can ensure you’ll have usable and valid backups when you useRMAN to back up those datafiles.■Tip Oracle recommends DBAs run proactive database checks, especially on those database componentsthat have received errors.In Oracle Database 11g, there is a new command called validate that has semanticallysimilar options as the older backup ... validate command but can validate at a much finerlevel of granularity. Whereas you could use the backup ... validate command at only thedatabase level, you can use the validate command to perform the same job at the backup set,tablespace, datafile, or even at the data block level. You may even use it to check the integrityof the flash recovery area or all recovery files.If you think there are failures that haven’t been trapped automatically by the database, runthe validate command to check for missing files and corrupt data blocks. The validate commandhelps you invoke a database health check to assess the failure when it finds any type of datafailure. RMAN logs the failure information in the ADR. You can then use the Data RecoveryAdvisor’s list failure, advise failure and repair failure commands in RMAN to view thefailures and repair them. By default, the validate command looks for physical corruption of