Page 1327 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

mission-critical machines, but they all serve an equal and
necessary purpose.

Damon, an information professional, learned this the hard way

when he lost months of work following a natural disaster that
wiped out the first floor at an information brokering firm. He never
used the backup facilities built into his operating system or any of
the shared provisions established by his administrator, Carol.

Carol has been there and done that, so she knows a thing or two
about backup solutions. She has established incremental backups
on her production servers and differential backups on her

development servers, and she’s never had an issue restoring lost
data.

The toughest obstacle to a solid backup strategy is human nature,
so a simple, transparent, and comprehensive strategy is the most
practical. Differential backups require only two container files (the
latest full backup and the latest differential) and can be scheduled

for periodic updates at some specified interval. That’s why Carol
elects to implement this approach and feels ready to restore from
her backups any time she’s called on to do so.

Backup Tape Formats

The physical characteristics and the rotation cycle are two factors that
a worthwhile backup solution should track and manage. The physical
characteristics involve the type of tape drive in use. This defines the
physical wear placed on the media. The rotation cycle is the frequency
of backups and retention length of protected data. By overseeing these

characteristics, you can be assured that valuable data will be retained
on serviceable backup media. Backup media has a maximum use limit;
after thousands of passes through the read/write head of a tape drive,
the media begins to lose reliability.

Disk-to-Disk Backup

Over the past decade, disk storage has become increasingly
inexpensive. With drive capacities now measured in terabytes, tape