ORACLE DBA BLOG

    Hot Backup : A hot backup is taken when the database needs  totally open and available to its users . It is an online backup. All files of the database are copied and there may be changes to the database during the copy. For the hot backup the database must be running in the ARCHIVELOG Mode. The benefit of taking a hot backup is that the database is available for use while the backup is occurring and one can recover the database to any point in time. For Hot Backup  the database must be informed when the backup is starting and when it is going to complete.    Alter database begin backup  Alter database end backup    Backup Procedure :  Gather all the Info for the backup Purpose .  select name from v$datafile ; select * from v$controlfile ; select name from v$logfile ; select NAME from v$archived_log ; create pfile from spfile ;   Perform a log switch and note down the old and current log  sequence of database  Alter system archivelog current  ; archive log list   ;  Place

 Cold Backup :  A cold backup is done when there is no user activity going on with the system. Also called as offline backup, is taken when the database is not running and no users are logged in. all files of the database are copied and no changes during the copy are made. Cold backup can be preformed when Database is in archive mode as well as Non archive log mode  . Backup Strategy :  Gather all the details of physical files (CRD) files in  database . redo log files are online redo log and archived redo log ones .   Select file_name,tablespace_name from dba_data_files  ; select * from v$controlfile  select member from v$logfile ; select name from v$archived_Log ;  create pfile from spfile  Backup  the contol file manually . alter database backup controlfile to trace as '/tmp/coldbackup_controlfile.sql' ;     Stop all the DB services (Database ,Listener)on source DB Server. Copy all the files(Datafiles,redologfiles,pfile,contol file backup) from source to backup location