*BSD News Article 68954


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From: les@MCS.COM (Leslie Mikesell)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: dump on a DAT tape ..
Date: 19 May 1996 23:47:49 -0500
Organization: /usr/lib/news/organi[sz]ation
Lines: 50
Message-ID: <4nothl$f3f@Mercury.mcs.com>
References: <4mfon3$gib@news.simplex.nl> <4miicv$sb9@uriah.heep.sax.de> <4nd0kh$1bm@anorak.coverform.lan> <4nlka4$1l5@uriah.heep.sax.de>
NNTP-Posting-Host: mercury.mcs.com

In article <4nlka4$1l5@uriah.heep.sax.de>,
J Wunsch <joerg_wunsch@uriah.heep.sax.de> wrote:

>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.

GNUtar fixes most of these problems.  Not sure about that last one.

>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. :)

Maybe, maybe not.  I want to be able to read back any tape on
any machine.

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

Ever try to write a cpio archive on sysvr4 that you can read on
earlier versions?  On a filesystem containing >64K inodes?  Not
a pretty sight.  Fortunately GNU cpio can be compiled for
non-svr4 systems to read the now-standard format.

>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,

GNUtar can do this too, although the documentation for the option
leaves a lot to be desired.

>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).

Tar isn't so handy in this respect.

Les Mikesell
  les@mcs.com