Sunday , October 22 2017



  1. What are the advantages of RMAN?
    1. Validation of the backup
    2. Parallelism
    3. Block level backup
    4. Incremental backup
    5. Recovery catalog etc
  1. Explain how RMAN performs the backup?
    1. When RMAN is initiated, it will start reading datafile headers for used block information. It will get that from bitmap blocks
    2. With that information, RMAN will copy blocks to the backup piece
  1. During RMAN backup we are getting “failed to create sequential file” error. What is the reason?
    1. The reason would be lost of contact with tape drive, so we need to check with backup team
  1. We are getting “control file enqueue” error in RMAN backup log file, what action you will take?
    1. It means two backups on same database are trying to take controlfile backup and one of the backup is placed in queue until first one completes
  1. What is your backup strategy?
    1. Daily we will take full RMAN backup for all prod databases and will take structural export backup. For dev and other environments, it is a weekly twice procedure. Apart from this, we have archive backup scheduled for all prod databases every 30min
  1. If you have a 2 TB database and need to design a backup policy, how you will do that?
    1. We need to choose RMAN incremental level 1 backup as it will complete faster. Weekend we will take full RMAN level 0 backup
  1. What is your backup retention policy is set to?
    1. 90 days
  1. What is the need of BACKUP OPTIMIZATION parameter in RMAN?
    1. It will help in avoiding to take backup of a datafile which is not changed when we are performing image copy of database through RMAN
  1. Why RMAN is best over other backup methods?
    1. Because it uses block level backup which reduces backup size and time
  1. What are the new features of oracle 10g RMAN?
    1. We have encryption of backup, using archive deletion policy etc
  1. What are the new features of Oracle 11g RMAN?
    1. We have some new commands like list failure, validate database etc and also we can now use virtual private recovery catalog
  1. What is the need of recovery catalog?
    1. Generally RMAN backup information will be stored in target database controlfile. In case we lost all controlfiles, it will be a problem in using existing backups. So recovery catalog is another database that to be configured, so that all the target RMAN backup information will now be stored in that
  1. Suppose we lost datafiles in recovery catalog, how to recover them?
    1. As recovery catalog is also a database, we will be performing backup for the same. Sowe can restore and recover from that backup
  1. What is mean by channel allocation in RMAN?
    1. It is allocating a medium to send backup to backup device
  1. If we don’t use recovery catalog, where the backup information is stored and till how many days?
    1. It will be stored in controlfiles and no of days are dependent on CONTROLFILE_RECORD_KEEP_TIME parameter. Generally it is 7 days
  1. How many recovery catalogs you will create for 100 prod databases?
    1. Only one is enough
  1. What are the advantages of differential and cumulative incremental backups?
    1. Differential will take incremental backup in a daily fashion where as cumulative will take backup so that it includes all the other day changes also
  1. If you are the DBA, will you choose differential or cumulative and why?
    1. I will choose differential because it will complete faster
  1. How RMAN performs incremental backup of database?
    1. RMAN will first gets block information from bitmap block
    2. It will start comparing block SCN with the last level 0 backup
    3. If block is changed, SCN will differ in which case RMAN will take backup otherwise not
  1. What is the difference between full backup and level 0 backup?
    1. Level 0 backup will try to compare the block SCN with last backup, it will fail and then performs backup where as full backup no comparison is required
  1. How can I make incremental backup faster?
    1. Using change tracking file in 10g
  1. I have a image copy of database, can we apply level 1 incremental backup on that and recover the database?
    1. Yes we can apply
  1. Which process is responsible in writing latest SCN to controlfiles which are re- created?
    1. Server process


Read More:



Check Also


ORACLE EXP/IMP & DATAPUMP INTERVIEW QUESTIONS How can i make export faster? By using DIRECT=Y …

Leave a Reply

Your email address will not be published. Required fields are marked *