There are many backup utilities available and they vary from simple ones appropriate for individual systems, to complex backup suites appropriate for managing backups for multiple production systems and clusters.
The simpler utilities generally provide file-level backups that are written to external media or even a remote network location. They frequently provide options for incremental backups, where only changed files are copied after the first, full backup. Mostly, these are command line utilities which can be scripted and executed periodically via a CRON job, although there are graphical front ends available. The disadvantage of most of these are that in the event you need to restore after a complete disk failure, you must have some other means of restoring the partition information correctly, and of recreating the boot sector information properly so the system will be bootable.
Among the more common of the simple utility commands are rsyne and tar. Frequently, these utilities are used in the more complex backup software to actually store the data. Ifyou use one of the EXT filesystems, the dump and restore commands are of particular interest, because they understand and take into account the filesystem's metadata and are thus faster and more efficient than the simpler copy utilities. The disadvantage, of course, is that restores may only be done to an equivalent EXT filesystem. Other utilities such as rsyne can restore to a completely different filesystem type, although certain metadata, such as file ownership and permissions, may be lost if the type is too different, such as backing up from an EXT4 filesystem and restoring to an NTFS partition.
More complex backup software is sometimes capable of so-called Bare Metal backups. These combine small, low-level backups of (or at least the ability to recreate) the non-filesystem structures such as the partition tables and boot sectors, with file-level backups of the filesystem contents. Many are multisystem backup solutions that can be administered from a central location and which can store the backups on various media in various locations. Usually, these multisystem suites include the ability to define and control backup schedules, contents, and locations as well as provide for off-site archiving.
