3
Backup
A “backup” refers to a copy of data comprised of files and programs that
is stored on an auxiliary storage device as protection against loss of data
from computer or disk device failure. In such an event, lost data can be recovered from the backup.
The following considerations should be taken when backing up data.
Chapter 8
• Back up data regularly on a daily, weekly, or monthly basis.
• Schedule a suitable time to back up data such as after business processes
are finished so that everyday work is not interrupted.
• For backup media, consider the time and cost the backup will require, and
choose one that can store all the backup data.
• It is normal practice to create primary and secondary backup files, and store
them in separate places to protect against file loss.
Computer system
(1)Backup files
Attempting to back up every file and registry on a personal computer is
time-consuming and requires media with a large capacity.
Since Windows and application software can be reinstalled and restored to
their initial state, it is normal practice not to back up either software.
Important files created by users and files that contain environment settings
are usually backed up.
However, the entire hard disk is backed up if a failure will cause major
ramifications.
(2)Choosing a backup method
Methods of backing up data based on recovery time and backup work load
are summarized below.
Type
Backup data
Recovery method
Full backup
All data on the disk.
Restore from full backup.
Differential
backup
Data that has
changed since the
last full backup.
Restore from full backup and last differential
backup.
Incremental
backup
Data that has
changed since the
last backup.
Restore from full backup and all incremental
backups performed
since the full backup.
Backup Recovery
time
time
Long
Short
Reference
Restore
“Restore” refers to returning content
that has been backed up on a disk device or other device.
Short
Long
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