[Balug-talk] The Great Archive in the Sky

David Alban extasia at extasia.org
Fri Nov 7 17:06:02 PST 2003

Hash: SHA1


I go to archive my 8 GB of mp3's to 8mm tape.

  mp3 host: laptop running red hat 7.3, kernel 2.4.18
            tar: gnu tar 1.13.25
            ssh: OpenSSH_3.1p1

  8mm host: old scsi pentium 133 system running red hat 9, kernel 2.4.20
            tar: gnu tar 1.13.25
            ssh: OpenSSH_3.5p1

Command to create tar archive, executed on laptop:

  cd / && tar --multi-volume --rsh-command=/usr/bin/ssh \
              -cvf scone:/dev/st0 mp3

The archive is happily created.  I go to do a "tvf" just for that warm
fuzzy feeling.  On the 8mm host, I execute:

  tar --multi-volume -tvf /dev/st0

It proceeds to list the mp3 files on the first tape.  It gets to the
last file on the first tape and prompts me for the second tape:

  -rw-r--r-- alban/alban  4520227 2003-03-08 19:12:43 mp3/pink_floyd/dark_side_of_the_moon/the_great_gig_in_the_sky.mp3
  Prepare volume #2 for `/dev/st0' and hit return: 

I eject tape 1, insert tape 2, wait sixty to ninety seconds and hit
return.  I get:

  tar: This volume is out of sequence

Bullshit.  I repeat the entire process (superstitious? who me?) and
recreate the two volume archive.  Again the archive creation goes
without a hitch.  Again I try to list the contents of the archive.
Again, after inserting tape 2 I get "out of sequence".

I notice in the gnu tar manual:

  Use --multi-volume (-M) on the command line, and then tar will,
  when it reaches the end of the tape, prompt for another tape, and
  continue the archive. Each tape will have an independent archive,
  and can be read without needing the other. (As an exception to
  this, the file that tar was archiving when it ran out of tape will
  usually be split between the two archives; in this case you need to
  extract from the first archive, using --multi-volume (-M), and then
  put in the second tape when prompted, so tar can restore both
  halves of the file.) 


I interrupt out of the current "tvf" process and simply do:

  tar tvf /dev/st0

with the second tape in the drive.  I get:

  M--------- 0/0         2519843 1969-12-31 16:00:00 mp3/pink_floyd/dark_side_of_the_moon/the_great_gig_in_the_sky.mp3--Continued at byte 2000384--

and then the rest of the archive lists like there was never a problem.

My guess is that if I ever restore from this archive, I'll lose that
one file.  No big deal in this case.  I'm going with this archive.  I
can re-rip the file if I lose it.

But what if the file lost really mattered?  What am I doing wrong?

My version of tar seems to be the latest stable version.  I can't find
anything later than 1.13 at <http://ftp.gnu.org/pub/gnu/tar/>.

Yeah, I know I could do multiple archives each small enough not to
span a tape, but I'd really like to get this multi-volume archive
thing working.

- -- 
Live in a world of your own, but always welcome visitors.
Cave fruticem.             http://extasia.org/cave-fruticem/
Come to sig-beer-west!     http://extasia.org/sig-beer-west/
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