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From: csb@gdwb.oz.au (Craig Bishop)
Newsgroups: comp.protocols.nfs
Subject: Re: Backup Program for PCNFS
Message-ID: <558@rome.gdwb.oz.au>
Date: 18 Dec 90 01:15:32 GMT
References: <90.348.08:58:51@ira.uka.de>
Organization: Geelong & District Water Board, Australia
Lines: 99

dbraun@i50s7.ira.uka.de writes:
>Is LifeLine, a program mentioned in the PC NFS manual a solution?
>Is there any public domain possibility.

We use Lifeline backup and it works very well. We also backup all
of our PC's (about 50) to an exabyte using lifeline in
combination with some software we wrote which allocated the
exabyte tape drive to the PC's which wish to backup.

Below is the README file for the pcbackup utilities we have
written. When time permits we were going to release the PC and
Unix scripts to the network.

------------------- Pcbackup README ---------------------------

PCBACK.BAT runs on the PC and is in control of the remote tape drive via
Lifeline tar.  However the remote server needs to be in control of who gets the
tape drive to avoid contention issues.

PCBACK does the following:

1.  sets the time from the server (not needed but nice to do!)

2.  gets the name of the server and the tape drive (allows this to
	be centrally controlled for all PCs and to split PCs across 
	two or more servers and/or tape drives)

3.  logout the user so that backup runs as nobody and most network
	drives are dismounted

4.  mount a special exported tmp area for handshaking (access control to
	tape unit)

5.  checks whether Homebase is loaded (if %HB% set), check whether %PC% is
	set (set in autoexec.bat) and checks syntax of
	command.  Should be PCBACK drive1 drive2 drive3 ... 
	e.g. PCBACK C D E to backup drives c,d,e

6.  creates flagfile  %PC%.rdy to tell Unix shell script that PC is waiting
	for backup.  Shell script (hereafter called pcbackup) sorts through
	the PCs waiting for backup according to creation time of various
	%PC%.rdy files

7.  wait for returned flagfile %PC%.go (check for its existence every 30
	seconds - at the end of the sleep check if we exitted sleep via
	^C) - also check if shell script is running (pcbackup.run should 
	exist)

8.  while waiting display the PC which is currently backing up (if any)

9.  create %PC%.drive (eg PC67.c) and the %PC%.chk (eg PC67.chk) flagfiles

10. execute the tar command

11. do points 7 to 10 for every other drive 

Note:  NFSDRIVE is set to Q (a networked drive) at the beginning of the file
and reset to C (where the real \NFS directory is kept).
Also since this runs as nobody and uses rsh, you must have a nobody usercode
with its .rhosts containing all your PC's on your server.

MAKE SURE YOU READ ALL THE COMMENTS ESPECIALLY IN THE SHELLSCRIPT.  THIS WILL
GIVE YOU A GOOD IDEA ON THE HANDSHAKING INVOLVED.  

IF A PC TIMES OUT (IE START THE HANDSHAKING AND THEN HANGS) THE WHOLE BACKUP
IS ABORTED.  THIS IS BECAUSE THE UNIX SERVER CANNOT DETERMINE IF ANY DATA
HAS BEEN WRITTEN TO THE TAPE.  IT THEREFORE CANNOT REPOSITION WITH GREAT 
CONFIDENCE.  (POSSIBLY IT COULD KEEP TRACK OF FILES WRITTEN AND REWIND THEN
SPACE FORWARD BUT IT DOESN`T HAPPEN THAT OFTEN THAT IT IS A PROBLEM.)

Addenda:

BACKUP.DB is not used since we specify the host and device in the actual tar
command and use defaults for anything else.  This includes using standard
block size and the standard dd utility on the Unix host.

Remember that pcbackup.sh running on the Unix host only controls who gets the
tape drive.  It doesn't (in fact can`t) enforce it either.  It does not talk
directly to the tar program and handles no data.  It waits for the PC to 
create PC??.RDY.  It creates a sorted list (by time) of the PCs ready to backup.
Starting with the top of the list it creates PC??.GO (?? is the first one).
PCBACK.BAT responds with PC??.CHK and PC??.drive and then starts backing up
the first drive.  When finished this drive it creates PC??.FIN if it has
another drive. It waits for PC??.go again etc. At the finish of all drives
it creates PC??.END.  The Unix host (pcbackup.sh) then resorts all the PC??.RDY
files and start at the top of the list.

tar from within PCBACK.BAT invokes dd on the Unix host and transfers the data.
This part of the procedure is totally independent of anything we have written.

-------------------------------------------------------------------

Craig Bishop			Geelong & District Water Board
Phone: +61 52 262506		61-67 Ryrie St Geelong
Fax:   +61 52 218236		Victoria 3220 Australia
-- 
Craig Bishop			Geelong & District Water Board
Phone: +61 52 262506		61-67 Ryrie St Geelong
Fax:   +61 52 218236		Victoria 3220 Australia