*BSD News Article 45030


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From: pi@bridge.bloomington.in.us (Raymond L. Gilbert)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Floppy-based tape drive questions.
Date: 4 Jun 1995 17:26:02 GMT
Organization: A FreeBSD Enthusiast
Lines: 74
Message-ID: <3qsqba$4hd@usenet.ucs.indiana.edu>
References: <kientzleD97Cru.3nw@netcom.com> <3qhckj$hpf@bonnie.tcd-dresden.de>
NNTP-Posting-Host: xyplex4-1-6.ucs.indiana.edu

Thus it was recorded by the prophets, joerg_wunsch@uriah.heep.sax.de said:
>Be warned however, that the ft driver maintainer for FreeBSD himself
>does _not_ recommend people using floppy tapes. 

	OK OK well the damage is done... a floppy-interface drive was
really all I could afford. :-) I've been using it for the last year.

>In addition to what Terry has already explained, let me tell'ya some
>reasons for using `dump' for regularly backups:
[many fine reasons deleted]

	Wow.  Sounds great.  OK you sold me!  I would love to use dump
for my regular system backups.  The question then becomes, how do I go
about doing this from a floppy-interface drive?
	I've been tar'ing stuff and piping it through /sbin/ft (note:
I'm still using 1.1.5.1R). The trouble is, piping something through
the ft command is just about the *only* way I can communicate with my
drive.  I can do things like:

% echo test | ft ; ft | cat
test

But something simpler like:

% echo test > /dev/ft0

(or rft0, etc) produce a page fault and reboots my system.  Similar
things happen when I try to pass my tape device along to tar or dump, eg

% dump -u0f /dev/ft0 /usr
% tar czvfp /dev/ft0 /usr
% tar czvfp - /usr > /dev/ft0

Is this a "feature" in the ft driver to only let /sbin/ft communicate
with /dev/[r]ft*, or is it a bug that's fixed in 2.0.5?
	Other questions with dump/ft: ft doesn't seem to handle
multiple volumes on a single tape.  Ideally, I'd like to do a full fs
backup on one tape, and do incremental backups on a second
multivolumed tape--this would let me keep my tape in my system and let
cron do the incremental backups, say once a week, then let me do a
full backup by hand maybe 4 times a year or something.  This is
something that's a pain in the ass to do with tar (involving
find-based scripts to figure out which files have been modified), but
seems ideally suited for dump.  I know dump uses inodes, but as for
tar I don't even know if it's handling my hard links properly or not.
How can I do this with the ft driver?
	Also, dump seems geared only to whole filesystems.  Well for
my FreeBSD system, I really don't want to backup /usr/src, /usr/bin,
/usr/sbin, etc etc.  In fact, I've tried to structure my directory
system so that all my local stuff is in /usr/users, /usr/local, and
/etc.  Does dump really require me to put all of this in a separate
filesystem? I've got a slow net connection, so it would be really neat to
save the release tarballs along with /usr/local and /usr/users in 4
separate volumes on one tape, then do incremental backups of my local
stuff only.
	Finally, I *am* able to use dump if I pipe it through ft, eg

% dump -u0f - / | ft

but ft just hangs if I try it for my /usr partition (strangely enough
it works for a secondary partition I have that's really small).  I saw
someone post this same problem on 4/25 (psonnek@skypoint.com if you're
reading this), but I never saw an answer posted. 
	Is dump (or Amanda which won't work if dump doesn't) really
the answer to my floppy-tape woes?  Or should I concentrate my time on
writing my own incremental tar scripts?


-- 
/----------------------------------------------------------------------------\
| Raymond L. Gilbert       | "...the present rule in computing the circle's  |
| pi@indiana.edu           |  area is entirely wrong..."                     |
| IUB Dept. of Physics     |  - Bill No. 246, Indiana State Legislature, 1897|
\----------------------------------------------------------------------------/