The "classical" method of data storage has always been tape drives. A number of SCSI and IDE tape drives are supported under DragonFly; no compatibility list exists at this point, though devices supported on FreeBSD-4 should work. Tape backup has several advantages: it is stable, relatively cheap, and can hold a large quantity of data. However, tape media is accessed in linear fashion, and so it can may take some time to retrieve data.
Tape speed can be improved by using larger block sizes. The 'b' option controls block size while using dump() or restore.
# dump 0abf 64 /dev/tapedevice /
# restore rbf 64 /dev/tapedevice
dd can be used to reshape data passing to and from a tape drive.
# tar czf - / | dd obs=64k of=/dev/tapedevice
# dd ibs=64k | tar xvzpf -
More recently, recordable optical media have become a viable option for backup media. The shelf life and price per megabyte of saved data is not as great as tape (as of this writing), but the recording equipment is relatively common for creating CDs, and becoming more so for DVDs.
A third media option is hard drives. While these are not as cheap as tape or blank optical media, they offer the ability, when mounted, to instantly access data, or to update existing records.
Whichever option is picked, the backup media, once filled, should be stored in a location physically separated from the source data. Time invested in backups is wasted if the backups can be lost in the same accident that destroys the original data.
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