ropiobl

Several common models are used in designing backup plans. Each has its own advantages and
disadvantages. Numerous methods have been developed to deal with backup archival; most of
them are evolutions of the three models discussed here:
Grandfather, Father, Son Method The Grandfather, Father, Son method is based on the phi-
losophy that a full backup should occur at regular intervals, such as monthly or weekly. This
method assumes that the most recent backup after the full backup is the son. As newer backups
are made, the son becomes the father, and the father, in turn, becomes the grandfather. At the
end of each month, a full backup is performed on all systems. This backup is stored in an offsite
facility for a period of one year. Each monthly backup replaces the monthly backup from the
previous year. Weekly or daily incremental backups are performed and stored until the next full
backup occurs. This full backup is then stored offsite http://h2obeta.law.harvard.edu/299191 , and the weekly or daily backup tapes are
reused (the January 1 incremental backup is used on February 1, and so on).
This method ensures that in the event of a loss, the full backup from the end of the last month
and the daily backups can be used to restore information to the last day. Figure 9.4 illustrates
this concept: The annual backup is referred to as the grandfather, the monthly backup is the
father, and the weekly backup is the son. The last backup of the month becomes the archived
backup for that month. The last backup of the year becomes the annual backup for the year.
Annual backups are usually archived; this allows an organization to have backups available for
several years and minimizes the likelihood of data loss. It’s a common practice for an organi-
zation to keep a minimum of seven years in archives.
The last full backup of the year is permanently retained. This ensures that previous years’ infor-
mation can be recovered if it’s needed for some reason.

Offsite Storage Offsite storage refers to a location away from the computer center where paper
copies and backup media are kept. Offsite storage can involve something as simple as keeping a
copy of backup media at a remote office, or it can be as complicated as a nuclear-hardened high-
security storage facility. The storage facility should be bonded, insured, and inspected on a regular
basis to ensure that all storage procedures are being followed.
Determining which storage mechanism to use should be based on the needs of the organiza-
tion, the availability of storage facilities, and the budget available. Most offsite storage facilities
charge based on the amount of space you require and the frequency of access you need to the
stored information.
Crafting a Disaster Recovery Plan
A disaster recovery plan helps an organization respond effectively when a disaster occurs. Disas-
ters may include system failure, network failure, infrastructure failure, and natural disaster. The
primary emphasis of this plan is the reestablishment of services and the minimization of losses.
In a smaller organization, a disaster recovery plan may be relatively simple and straightfor-
ward. In a larger organization, http://wedrfgtqqq.blackapplehost.com/ it may involve multiple facilities, corporate strategic plans, and
entire departments. In either case, the purpose is to develop the means and methods to restore
services as quickly as possible and to protect the organization from unacceptable losses in the
event of a disaster.
A major component of a disaster recovery plan involves the access and storage of information.
Your backup plan for data is an integral part of this process. The following sections address
backup plan issues and backup types. They also discuss developing a backup plan, recovering a
system, and using alternative sites. These are key components of a disaster recovery plan: They
form the heart of how an organization will respond when a critical failure or disaster occurs.
Backup Plan Issues
When an organization develops a backup plan, it must be clear about the value of the informa-
tion in the organization. A backup plan identifies which information is to be stored, how it will
be stored, and for what duration it will be stored. To do this, you must look at the relative value
of the information you retain. To some extent, the types of systems you use and the applications
you support dictate the structure of your plan.
Let’s look at those different systems and applications:
Database Systems Most modern database systems (such as Oracle and Microsoft SQL Server)
provide the ability to globally back up data or certain sections of the database without difficulty.
Larger-scale database systems also provide transaction auditing and data-recovery capabilities.