0 Cold BackUp or physical backup

  • In oracle DBA we know that backup is an one of the important concept let us discuss about cold backup.
  • There are two types of backup 1) cold backup 2) hot backup
  • We need to shutdown the database and we need to take the backup of control file,redo log file, and database file at os level
  • In case of database running with No Archive Log mode then we can only go for simple restore after going through crash
  • If it is in Archive Log mode we can either go for Simple Restore or restore+recovery
  • Simple restore can even be performed by os admin where as recovery required DBA admin
  • Recoveries are of two types 1) Complete recovery  2) Incomplete Recovery
  • Complete recovery is possible only when we have 1)present Control file 2)current online redo log file
  • If any of the above two files missing then we end up with going for instance crash recovery
  • Complete recovery is possible in two ways
  1.  Online----Both system and undotbs datafile must be present
  2. Offline-----Any datafile can be missing
  • Instance crash recovery offers three choices
  1. Until cancel--Apply all the available archives  logs against latest cold backup-this is how offers us maximum recovery until time
  2. We can recover assuming archives are avilable upto time based recovery
  • Until SCN number---recover upto specified SCN number using archives logs
  • At the end of ICR we must reset logs then only we can open database.           

Oracle DBA Tutorial Copyright © 2011 - |- Template created by O Pregador - |- Powered by Blogger Templates