*BSD News Article 68888


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From: j@uriah.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: dump on a DAT tape ..
Date: 18 May 1996 22:51:48 GMT
Organization: Private BSD site, Dresden
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brian@awfulhak.demon.co.uk (Brian Somers) wrote:

> : I prefer dump(8) for full backups.

> IMO, tar is infinitely better.

tar is inherently broken.  It only allows for 100 (or 255 -- Posix
tar, but that's already another restriction) characters path name
length, many tar's don't allow for device nodes or FIFO's, tar has
problems extracting hardlinks if you wanna extract a subtree only, not
all tar's handle the permissions correctly.  tar's that can handle
device nodes still break for 32-bit major/minor numbers as they are
found in 4.4BSD descendants.

tar is certainly the least common denominator, but that doesn't make
it a good _backup_ program, only a good _data interchange_ program.

(Don't tell me you won't be able to find another machine using UFS
around. :)

cpio has fewer braindamages than tar, particularly SVR4 cpio.  Older
cpio's are not much better however.

dump/restore are only sharable among UFS architectures (and you will
even find byteorder stuff in restore, suggesting it's possible to
e.g. restore a SunOS 4 dump tape on FreeBSD!), but have the advantage
to be featured for a good backup program.  They don't suffer from any
of the abovementioned braindeadnesses, and offer some other nice
features like a multilevel incremental backup system that is even
capable of deleting files that disappeared on the master between the
backup increments, a TOC that's right at the beginning of your 5-tape
backup, and the ability to interactively determine which files to
restore (in a simple command-line shell-like interface).

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)