Backup
Backup: The most important aspect of any disaster plan is to maintain adequate backup copies. With careful planning, organization, and enough money, firms are able to provide virtually continuous information system support.
Hotsite: One level of support, called a hot site, consists of a fully configured computer center. Specific computer equipment is already installed and ready for immediate use.
Coldsite: Another alternative is to contract for a cold site, which provides fully functional computer room space, without the computer equipment. If a disaster occurs, either the company or the disaster recovery services provider can arrange for the necessary equipment to be shipped to the cold site. However, there might be a delay of several days before the new data center will be operational, so a cold site is often used in conjunction with a hot-site contract. Also see difference between cold site and hot site.
The problem with the traditional approach is that companies can no longer afford to run without computer support—even for a few hours. Fortunately, computer prices have also declined while network transfer speeds have increased. Consequently, it is possible for many companies to provide continuous backup—both in terms of data and processing capabilities.
In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "back up", whereas the noun and adjective form is "backup".[1] Backups can be used to recover data after its loss from data deletion or corruption, or to recover data from an earlier time.[2] Backups provide a simple form of disaster recovery; however not all backup systems are able to reconstitute a computer system or other complex configuration such as a computer cluster, active directory server, or database server.[3]
A backup system contains at least one copy of all data considered worth saving. The data storage requirements can be large. An information repository model may be used to provide structure to this storage. There are different types of data storage devices used for copying backups of data that is already in secondary storage onto archive files.[note 1][4] There are also different ways these devices can be arranged to provide geographic dispersion, data security, and portability.
Data are selected, extracted, and manipulated for storage. The process can include methods for dealing with live data, including open files, as well as compression, encryption, and de-duplication. Additional techniques apply to enterprise client-server backup. Backup schemes may include dry runs that validate the reliability of the data being backed up. There are limitations[5] and human factors involved in any backup scheme.
