Oracle recommends that database has minimum of four control files - Oracle Control Files

Discussion

• Nirja Shah   -Posted on 28 Aug 15
  - The true statement is:
  
  - Oracle strongly recommends that your database has a minimum of two control files and that they are located on separate physical disks.
  
  - Every Oracle Database should have at least two control files, each stored on a different physical disk.
  
  - If a control file is damaged due to a disk failure, the associated instance must be shut down.
  
  - Once the disk drive is repaired, the damaged control file can be restored using the intact copy of the control file from the other disk and the instance can be restarted. In this case, no media recovery is required.
  
  - The behavior of multiplexed control files is this:
  
  1. The database writes to all filenames listed for the initialization parameter CONTROL_FILES in the database initialization parameter file.
  2. The database reads only the first file listed in the CONTROL_FILES parameter during database operation.
  3. If any of the control files become unavailable during database operation, the instance becomes inoperable and should be aborted.
  
  - One way to multiplex control files is to store a control file copy on every disk drive that stores members of redo log groups, if the redo log is multiplexed.
  
  - By storing control files in these locations, you minimize the risk that all control files and all groups of the redo log will be lost in a single disk failure.

➨ Post your comment / Share knowledge