How to Handle Data Loss and Backup - High-Performance Web Databases: Design, Development, and Deployment - page 714

be read without reloading the original software (if it can be found at
all) or running routines of varying complexities to convert the data
into compatible formats.
• The destruction of a building or a work area within it by fire, earth-
quakes, temperature extremes, flood, or other such catastrophes that
render diskettes or tapes unreadable or unavailable.
Once lost, data cannot be replaced. Accepting this fact, the prudent user
routinely backs up data to a medium and location that together guarantee
that no single disaster can destroy both the primary electronic source
record and the backup copy simultaneously. Choosing a procedure that
protects an organization from anything from accidental data erasure to
data destruction in a building fire is the first step in creating a workable
backup routine.
SIX BACKUP OPTIONS
There are six principal backup options. They are discussed in the follow-
ing sections.
Do Nothing
Many now follow this course. They risk the complete loss of their data files.
Use Magnetic Tapes and Diskettes and Carry Them Off-Site
This method is the cheapest and the most commonly used. However, it
involves many potential problems in cataloging, maintaining, and recover-
ing data.
The traditional method of assigning data owners the responsibility of
regularly backing up data and storing it on a diskette does not work for two
main reasons. First, users take diskettes containing their backup copies
home at the end of the work day, compromising the security of these back-
ups. Second, users stop backing up data regularly when their files grow to
require multiple diskettes. When the backup process annoys the data
owner, the manual backup procedure is dead.
Centralizing all backup activities and having them performed by specific
individuals does not work either. The backup records become sloppy, and
labeling them becomes an administrative nightmare. The people responsi-
ble for making backups leave the organization, or they have new responsi-
bilities that interfere with the backup process. As a result, the backups are
made less frequently, and eventually the backup process stops altogether.
Tape backups can be made automatically. But tape drives can be expen-
sive, and the time necessary to write to tape can be long, especially if the
backup is done in the verify mode. Tape drive heads also become dirty,
diminishing the quality of backup information.