## 38.14. Industrial Strength Backups

This book mostly focuses on tools like tar, because that's what we expect most of you to use most of the time. However, there are other tools that are very important for large-scale backups that it's good to know at least a little about.

dump is an old Unix standby and a complete if somewhat arcane tool for backing up file systems. It is extremely useful for system administrators and personal machines, and it is available as part of the operating system on nearly any Unix. For industrial-strength backups, no simple solution beats dump -- it is the most reliable tool for ensuring data consistency and stability. It's also a pain to use, so generally system administrators end up writing scripts around it to make it easier, or using a system like Amanda (see below).

The Advanced Maryland Automatic Network Disk Archiver, known as Amanda, is a free system for performing regular backups of one or more network-connected machines. Information on Amanda is generally available at http://www.amanda.org. Amanda uses tar or dump to do the actual work of backing up files; its job is to coordinate backups of multiple filesystems to one or more network-accessible tape drives on a regular basis.

Note also that full-scale backup processes need to address things such as tape lifetimes, electronic and physical security of backed-up data, off-site storage, incremental backup schemes and the like. Should you be in a position to need to set up such a process, read one of the good books on the subject -- we might recommend O'Reilly's Unix Backup and Recovery.

-- DJPH

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