Describe the Oracle backup, i.e. archive log
mode, cold and hot backups, incremental backups.
Oracle backup - Feb 14, 2009 at 15:00 PM by Amit Satpute
What is archive log mode?
The archiving of the redo log is enabled by running database in ARCHIVELOG mode.
A group of filled redo log files cannot be reused by LGWR until the group is
archived and become available for archiving immediately after a redo log switch
occurs.
Advantages of archiving the filled groups:
-
A database backup, together with online and archived redo log files, guarantees
recovery of all committed transactions in the event of an operating system or
disk failure.
-
In an archived log, the backup is taken while the database is open and in
normal system use.
-
The standby database can be kept current with its original database by
continuously applying the original archived redo logs to the standby.
Explain cold and hot backups.
A backup taken when the database is not running is called a cold backup.
This is also known as an offline backup.
Copying physical files when the database is up is called hot back up.
It is done by putting the tablespace in backup mode and then copying all the
data file using the copy commands and then bringing it back to normal state.
What are incremental backups?
Incremental backup stores all files that have changed since the last FULL,
DIFFERENTIAL OR INCREMENTAL backup.
Its advantage is that it takes very less time to complete.
But the restore operation is lengthy as each incremental backup must be
processed.
The answers to following questions will be made available
soon. Keep visiting.
Backups vs. RAID.
Also read
How do you increase the performance of %LIKE operator?, What is a standby
database? Difference between Physical and logical standby databases, What is
Cache Fusion Technology?, What is simple replication and advance
replication?.............
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........
What is an Index?, What are the objects in oracle?, What is
INDEX_BY_BINARY_INTEGER?, What is index and explain its purpose...........
Tablespace fragmentation can be prevented by using PCTINCREASE command.
PCTINCREASE is the percentage a new subsequent extent will grow...............
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