Page 1328 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

and optical media can’t cope with data volume requirements anymore.
Many enterprises now use disk-to-disk (D2D) backup solutions for

some portion of their disaster recovery strategy.

Many backup technologies are designed around the tape paradigm.
Virtual tape libraries (VTL) support the use of disks with this model
by using software to make disk storage appear as tapes to backup
software.

One important note: Organizations seeking to adopt an entirely disk-
to-disk approach must remember to maintain geographical diversity.
Some of those disks have to be located offsite. Many organizations

solve this problem by hiring managed service providers to manage
remote backup locations.

As transfer and storage costs come down, cloud-based

backup solutions are becoming very cost effective. You may wish to
consider using such a service as an alternative to physically
transporting backup tapes to a remote location.

Backup Best Practices

No matter what the backup solution, media, or method, you must
address several common issues with backups. For instance, backup
and restoration activities can be bulky and slow. Such data movement

can significantly affect the performance of a network, especially during
regular production hours. Thus, backups should be scheduled during
the low peak periods (for example, at night).

The amount of backup data increases over time. This causes the
backup (and restoration) processes to take longer each time and to
consume more space on the backup media. Thus, you need to build
sufficient capacity to handle a reasonable amount of growth over a

reasonable amount of time into your backup solution. What is
reasonable all depends on your environment and budget.

With periodic backups (that is, backups that are run every 24 hours),
there is always the potential for data loss up to the length of the