Network - Backup
A backup is an archival copy that is stored on an external medium. For example, a backup might contain the contents of a hard disk or a directory. The creation of regular backups is essential in a networking environment. An effective backup system ensures that data stored on the network can be recreated in the event of a crash or another system failure. Networking packages differ in the type of backup supported, in the media to which material can be backed up, and in the ease with which parts of the archived material can be restored. Backups are generally made to tape or to erasable optical (EO) media. No serious network should be backed up to floppy disks. Various types of backups are distinguished, including full, differential, and incremental. In full backups, a copy is made of all the data. In differential and incremental backups, only the data that has been added or changed since the previous backup is included. Differential and incremental backups assume a full backup has been done and they merely add to this material. Such backups use the Archive flag (attribute), which is supported by DOS and most networking environments. This flag is associated with a file and is set whenever the file is changed after the file is backed up. 84 Backup The backed up material should generally be stored in a different physical location from the original material, and should be protected from disasters such as fire, flood, magnets, theft, and so on. Backup operations should be done at a time when the network is not being used for its ordinary activity, which generally means outside regular working hours. One reason for this is that most backup programs will not back up a file that is open. Truly, the work of a system administrator is never done. When you restore the data, you restore the last full backup first, then restore each incremental backup made since the last full backup. A BACKPLANE 486 DX Jumpers Expansion Slots Keyboard Connector Slot for Optional Memory Card Memory Chip Slots Coprocessor CPU Dip Switches Power Connectors BIOS Chips SEE ALSO Archive RELATED ARTICLES Data Protection; Disk Duplexing; Disk Mirroring