NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/comp/unix/ultrix/9044

Internet Message Format | 1992-12-22 | 3.4 KB

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Path: sparky!uunet!haven.umd.edu!decuac!pa.dec.com!nntpd2.cxo.dec.com!nabeth!alan
From: [e-mail] (Alan Rollow - Alan's Home for Wayward Tumbleweeds.)
Subject: Re: Backup procedure sought
Message-ID: <[e-mail]>
Keywords: Ultrix 4.3 backup dump tape date
Lines: 57
Sender: alan@nabeth (Alan Rollow - Alan's Home for Wayward Tumbleweeds.)
Reply-To: [e-mail] (Alan Rollow - Alan's Home for Wayward Tumbleweeds.)
Organization: Digital Equipment Corporation
References:  <[e-mail]>
Date: Tue, 22 Dec 1992 20:24:05 GMT


In article <[e-mail]>, [e-mail] (Mads Westermann) writes:
>
>I'm running an Ultrix 4.3 system on a DECSystem 5100 having three rz24 disks
>and two rz57 disks. The disks are partitioned into eight different file-
>systems. I need a backup procedure that (unattended) will bring the system
>into single-user mode, do a full or an incremental backup on *ONE* tape
>and then bring the system back into multi-user mode again. I have read
>the docs for dump(8) over and over again, and to me it seems like there is
>no way to make dump put more filesystems on the same tape.

How to put multiple backups on one tape is sort of documented, just
not very well.  Fill out a Reader's Comments page for Guide on backups
and mail it to us, this sort of thing needs to be cleared up.  The
solution is pretty simple.  The 'f' option of dump(8) allows writing
to a different device than the default (/dev/rmt0h).  If you write to
a no-rewind tape device, then each new dump will start after the last
one.  For example; if you typically use "dump 0u /", change it to
"dump 0uf /dev/nrmt0h /".  Note the 'n' at the beginning of the tape
device name.  This is the naming convention for no-rewind tape devices
(See also mtio(4)).

> and Also
>it seems to me that there's no way to bring the system into single-user
>and back into multiuser mode unattended ?

1.  Make sure the worst likely case backups will fit on one tape.  If
    you run out of tape the way you intend to use dump(8), it will
    occassionally ask you for the next tape.  The system will be stuck
    in single user until you answer it.  Of course this may be what you
    want.

2.  Clue: When the transition is made from multi-user to single user, init
    starts an sh(1).  When this sh(1) starts it performs the shell commands
    in .profile.  It should be possible to replace .profile with a script
    that unmounts the file system, runs dump and does whatever you want
    done running single user.  Then you want to replace .profile with the
    original one and have the shell kill itself.  This should transition
    backup to multi-user.  I did this once on ULTRIX V1.something when
    I worked at the CSC.  I didn't save the .profile, but it was pretty
    easy once I figured out how to have the shell kill itself.  I think
    I just sent a signal using kill(1) to the process id $$.

>
>Has anybody solved this problem ?? I'd very much appreciate if you
>could enlighten me on this subject.
>
>Rgds.
>--
> Mads Westermann                | Phone:        [phone]
> Damgaard Data Distribution A/S | Fax:          [phone]
> Bregneroedvej 133              | E-mail:       [e-mail]
> DK-3460 Birkeroed, Denmark     | UUCP:         ..!uunet!dd.dk!wes
>
--
Alan Rollow                [e-mail]