[Info-vax] strange backup behavior

[AEF]

On Aug 10, 2:02 pm, B Hobbs <bdhobb... at acm.org> wrote:
> On Aug 10, 10:10 am, AEF <spamsink2... at yahoo.com> wrote:
>
>
>
> > On Aug 10, 11:48 am, B Hobbs <bdhobb... at acm.org> wrote:
> > > On Aug 8, 9:42 am, AEF <spamsink2... at yahoo.com> wrote:
> > > > On Aug 8, 9:07 am, sapienzaf <sapie... at noesys.com> wrote:
> > > > > On Aug 7, 11:55 pm, David J Dachtera <djesys... at spam.comcast.net>
> > > > > wrote:
>
[...]

> > The .com file would be helpful.
>
> Posted separately.

Thank you; I'll take a look.
>
>
>
[...]

> > Are you perhaps running $ set magtape/log/skip=end_of_tape mua0:
> > between each backup? You don't need to do that, though I don't know if
> > this might be causing your problem.
>
> Just the one skip after the initial MOUNT/FOREIGN.  This is so backups
> are added to the tape and not written over existing files.  I
> INITIALIZE the tapes manually when needed.
>
> Hmmm, maybe I should try SET MAGTAPE/SKIP=END_OF_TAPE between each
> backup step ...  Suggestions or thoughts?

No. You don't need it at all. /NOREWIND is sufficient and I believe
that's the default. It is in my version, V6.2. I can't believe they'd
change that as VMS generally made it hard to overwrite data.

> > > > To the OP: Why are you not using /IMAGE instead of /FAST [000000...]?
> > > > Why are you making both a journal file and listing file of each save
> > > > set?
>
> > Come to think of it, I don't think /FAST buys you anything for full
> > backups. It's really useful  as follows:
>
> > A fast file scan is most useful when the input specifier includes most
> > of the files on the volume, and file-selection qualifiers (such as
> > those that pertain to date or owner) specify a relatively small set of
> > the files named. Because image operations implicitly use the fast file
> > scan, the /FAST qualifier is ignored if used with the command
> > qualifier /IMAGE.
>
> > > The procedure loops thru the disks, executing pretty much the same
> > > backup command on each disk.  There is an embedded symbol in the
> > > backup command that shows up as an empty continuation line for most of
> > > the disks, for some disks this symbol contains an /exclude.  /Image
> > > ignores /exclude, it was simpler to use the same command for all
> > > disks.  It wouldn't be difficult to change to /image for some disks,
> > > but I didn't see much advantage from reading the documentation.
>
> > BACKUP/IMAGE preserves volume characteristics (everything you specify
> > with the INIT command, and subsequent SET VOLUME commands). It also
> > preserves aliases. Lost files and files marked for deletion are also
> > saved. It also provides a functionally equivalent copy. This is not
> > necessarily the case with non-image backups.
>
> > I would also guess that restore operations from /image backups would
> > go faster as directories don't need to be updated for each file
> > restored.
>
> > You can set the files to exclude as "backups disabled" using SET FILE/
> > NOBACKUP depending on the nature of the files. This is done by default
> > for page, swap, and system dump files on the system disk, as data in
> > them is useless after a crash or shutdown. If this is not the case for
> > these files, then why aren't you backup them up? I'm just asking.
> > Perhaps they're easier to regenerate than to restore from tape.
>
> Maybe I'll switch to /IMAGE and do a SET FILE/NOBACKUP on the
> offending files ... I need to consult with the powers that be.

Oh, the one *possible* problem with SET FILE/NOBACKUP for your
exlcudeable files is that upon restore it creates an empty file with
the same name and atributes. This is exactly what you want for page,
swap, and system dump files, but may not be what you need.

>
>
>
> > Why to you use /LOG, /JOURNAL, and /LIST? Isn't that rather redundant?
>
> This command procedure replaces three procedures from a third party.
> I'm trying to do what they did, with more control, and using a single
> tape drive.  Their procedures ran independent of each other and used
> two tape drives.  Their procedures had "belts *and* suspenders", so I
> did the same.

OK.

I'm experimenting with appending backup save sets on an 8mm drive. I
have DLT, but no scratch tapes to play with. I'll report back when I'm
done.

AEF