Available resources are another important consideration when selecting a
backup strategy. Backups require time, money, and personnel. Begin your
planning activities by determining what limitations you face for all these
resources. Then construct your plan to fit those limitations—or be prepared to
justify the need for more resources with a careful assessment of both backup
needs and costs.
TIP
If you are not willing or able to assess your backup needs and choose a
backup solution, you can choose from the legions of consultants, hardware
vendors, and software vendors that are available to assist you. The best way
to choose one in your area is to ask other UNIX and Linux system
administrators (located through user groups, discussion groups, or mail
lists) who are willing to share their experiences and make
recommendations. If you cannot get a referral, ask consultants for
references and check them out.Many people also fail to consider the element of time when formulating
backup plans. Some backup devices are faster than others, and some recovery
methods are faster than others. You need to consider that when making
choices.
To formulate a backup plan, you need to determine the frequency of backups.
The necessary frequency of backups should be determined by how quickly the
important data on your system changes. On a home system, most files never
change, a few change daily, and some change weekly. No elaborate strategy
needs to be created to deal with that. A good strategy for home use is to
backup (to any kind of removable media) critical data frequently and backup
configuration and other files weekly.
At the enterprise level on a larger system with multiple users, a different
approach is called for. Some critical data changes constantly, and it could be
expensive to re-create this data because doing so typically involves elaborate
and expensive solutions. Most of us exist somewhere in between these
extremes. Assess your system and its use to determine where you fall in this
spectrum.
Backup schemes and hardware can be elaborate or simple, but they all require
a workable plan and faithful follow-through. Even the best backup plan is
useless if the process is not carried out, data is not verified, and data
restoration is not practiced on a regular basis. Whatever backup scheme you
choose, be sure to incorporate in it these three principles:
Have a plan—Design a plan that is right for your needs and have
equipment appropriate to the task. This involves assessing all the factors