You can back up a Linux system, or a portion thereof, using any of many different programs. Some of the more popular programs for creating backups include the following:
AMANDA The Advanced Maryland Automatic Network Disk Archiver (AMANDA) is a powerful network-based backup tool. It builds on dump or tar to enable one computer to serve as a backup station for potentially dozens of other computers. The project's home page is http://www.amanda.org.
BRU The Backup and Restore Utility (BRU) is a commercial backup package for Linux and other Unix-like systems. It creates an archive of backup files at the start of the backup, so you can easily view a list of backed-up files and select those you want to restore from the list. It can be used to back up individual systems or an entire network. The core utility is text-based, but BRU also comes with a unique GUI front-end. You can read more at http://www.bru.com.
cp The standard Linux cp command can be used to create backups on disk media, but not on tapes. Ordinarily, cp modifies file characteristics, such as the owner; however, if you add certain options, such as -a, cp does a better job of preserving this information.
cpio This program is a popular archiving tool for Linux. You can use it to create an archive directly on a tape, or you can pipe its output through cdrecord to create a cpio-format optical disc.
dump This program works at the inode level, which means that the program does a better job backing up files without modifying characteristics such as last-access date stamps and hard links than do most other backup tools. This feature also means that the program is highly filesystem-specific, though. Versions for ext2fs/ext3fs (dump) and
XFS (xfsdump) are available, but they produce incompatible archives; you can only restore to the type of filesystem from which you backed up. This program relies on a companion program, restore, to restore data.
smbtar The Samba package for file and printer sharing with Windows systems comes with a script called smbtar. This script combines the smbclient and tar programs, permitting a Linux system to back up Windows clients. The Windows clients must have file sharing enabled, though.
tar The tar program has long been a staple in the Linux world. It's conceptually very similar to cpio, but tar has become the standard archive format for exchanging file collections on the Internet. Its name stands for tape archiver, so as you might expect, it can be used to archive a filesystem directly to tape. You can also use it with cdrecord to create a tar-format optical disc.
As a general rule, tar is the most popular and lowest-common-denominator backup tool, but it's not always the best choice. AMANDA and BRU are particularly worthy of note for backing up a network. AMANDA includes automatic backup scheduling tools that can greatly simplify the backup and restore procedures. The cost is that AMANDA, on both the backup server and its clients, takes a great deal of effort to configure.
Warning Most backup programs don't encrypt their data. An unauthorized individual who obtains your backup can read sensitive data, even if the files have restrictive permissions on the original hard disk. Therefore, you should treat backup media as you would other sensitive documents. If you deal in unusually sensitive data, you may want to consider adding encryption to your backups to protect them in the event they're stolen or "borrowed."
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