Unix Backup and Recovery

Comparing tar, cpio, and dump

A few years ago, John Pezzano from Hewlett-Packard did a paper comparing native backup products. It is the best one that I have seen, so I asked his permission to update it and include it in this book. It is Table 3-5.

Table 3-5. Conversion of Native Utilities

Feature	tar	cpio	dump
Simplicity of invocation	Very simple (tar c files)	Needs find to specify filenames	Simple—few options
Recovery from I/O errors	None—write your own utility	Resync option on HP-UX will cause some data loss	Automatically skips over bad section
Back up special files	Later revisions	Yes	Yes
Multivolume backup	Later revisions	Yes	Yes
Back up across network	Using rsh only	Using rsh only	Yes
Append files to backup	Yes (tar -r)	No	No
Multiple independent backups on single tape	Yes	Yes	Yes
Ease of listing files on the volume	Difficult—must search entire backup (tar -t)	Difficult—must search entire backup (cpio -it)	Simple—index at front (restore -t)
Ease and speed of finding a particular file	Difficult—no wildcards, must search entire volume	Moderate—wildcards, must search entire volume	Interactive—very easy with commands like cd, ls
Incremental backup	No	Must use find to locate new/modified files	Incremental of whole filesystem only, multiple levels
List files as they are being backed up	tar cvf 2> logfile	cpio -v 2> logfile	Only after backup with restore -t > logfile (dump can show % complete, though) ...