information are as important for an organization as blood in human body.
In case data and information become unavailable due to any reason, all
the working of the organization stops and it becomes unmanageable loss.
In order to avoid such big loss, Database Administrator (DBA) must take
backup of his database frequently according to the nature of the
database. Normally full backup are done after one week but incremental
backup are done on daily basis. Backup can be defined as second copy of
original database produced by backup facilities provided by DBMS or
operating system. This second copy or saved copy of original database is
produced on separate storage media such as magnetic tape, external hard
disk and on CD-drives. These should be placed in a separate and secure
location, where unauthorized persons do not have any access. The best
way, you can store your database backup online using Internet and you
can access this backup any time, from any location using Internet. There
are two important types of backup.
You can say
hot backup is dynamic or active backup. Hot backup is taken when
database is running and data is being updated, added, or read by its
users but doesn’t handle running transactions. Only database
management system (DBMS) facility can be used to take hot backups.
Make sure that hot backups should only be done during low working
hours. Hot backup is taken in environments where database needs to
remain online 24-hours a days and 7-days a week, because they do not
require downtime as in cold backup.
Cold backup is
taken when database is offline,
not accessible for updating and users
do anything on the database..
DBMS as well as operating system facilities can be used to take the
cold backup. Normally, cold backup is taken at the end of a working
day or at weekends when database comes offline. Cold backup is
suitable in environments where database is not running 24-hours a
day. Instead, there are sometime intervals when it remains off.
Backups can be
taken manually through the DBA or these can be taken automatically
by configuring the DBMS. In case of automatic backups, you must
specify day, time, and location on storage media where DBMS will
take the backups. These settings are required when configuring the