Backup is a copy of important data for security reasons.

What is BACKUP (in computer networking)?

A copy of important data. Performing regular backups is one of the main components of a company’s disaster recovery policy, and the importance of doing so cannot be stressed enough. Various occurrences can lead to data loss on a corporate network:

  • Disk failures caused by hardware failure, power outages, or improper use
  • Network problems leading to lost packets that are not acknowledged because of router congestion or other situations
  • Virus infection, resulting in corrupted files
  • Sabotage by hackers or disgruntled employees, resulting in erased data
  • Theft of hardware from the premises

To guard against these occurrences—or rather, to prepare for them, since they are, to a certain extent, inevitable—establish a disaster recovery policy that includes a reliable backup plan. In today’s business world, where data is the lifeblood of the enterprise, a comprehensive plan is essential. The following steps are recommended when creating such a plan:

  • Decide what kind of backup storage devices to use. Options range from small digital audio tape (DAT) drive units capable of backing up several gigabytes of data, to large automated tape libraries capable of handling terabytes of centralized data storage. Other backup options include optical storage libraries and removable disks such as Iomega’s Zip drive disks or Imation SuperDisk disks.
  • Decide whether to back up servers with dedicated, locally connected storage devices or over the network to centralized backup libraries. Network backup systems suffer from a single point of failure (the network itself) but are simpler to administer than a multitude of individual backup units.
  • Decide whether individual users’ workstations should also be backed up. A more cost-effective option is to educate users to always save their work on a network share located on a server that is regularly backed up.
  • Decide how to secure the storage of backup tapes and other media. Will duplicate copies be stored both on site (for easy access if a restore is needed) and off site (in case the company’s building burns down)? Make sure the storage facilities are climate controlled and secure.
  • Decide what kind of backup strategy to employ. A backup strategy is a combination of a backup schedule and various backup types, including normal, copy, incremental, differential, and daily copy backup types. Also consider whether you will verify all tapes immediately after each backup is performed.
  • Assign various aspects of the backup procedure to the responsible party. One option some companies now use is to back up data over the Internet to a third-party backup service provider that stores and maintains the backed-up data. This method involves issues of trust and of the Internet connection as a point of failure.
  • Test backups periodically to ensure that they are actually readable. Nothing is worse than thinking you have a backup when in fact it is unreadable.

To enable administrators to perform regular backups, Microsoft includes backup utilities with all versions of Microsoft Windows, such as the Backup tool in Windows 2000.