Face untar problem

[Achilles_2]

Hi all,

I have encountered the problem about untar the tape in HP-UX 11.00 machine. The status of driver and tape are:

Drive: HP C1537A
Format: DDS-2 format

I extract it via unix command:
> tar tv /dev/rmt/0m

and then it shows the following errors
Tar: blocksize = 2
directory checksum error

Any suggestions welcome

Alex

[Patrick Wallek]

That error could be several things.

1) Are you absolutely positive that the tape was created with tar? If it wasn't tar will NOT work to extract the files.

2) The tape could have gone bad. Can you read other tapes? Have you tried running a cleaning cartridge through the drive?

3) The tape was create with a different block size than the default. Can you talk to the person that created it?

4) Was it created with tar on a different type of Unix system? Was it created with Gnu tar rather than the normal HP-UX tar?

At this point we don't have a whole lot to go on.

[T G Manikandan]

I would add

First check which backup format the tape is,

#dd if=/dev/rmt/0m of=/tmp/tapeformat bs=1K count=2

Now check that file as which backup format is that.

Then you can proceed.

[Achilles_2]

Hi,

I checked that the tape is created using "make_tape_recovery" method and created under HP-UX 11.0. It is the same as my machine.

How to able to read its content and extract some files on the tape.

Thanks you for your help.

Alex

[T G Manikandan]

Then do a

#mt -f /dev/rmt/0mn fsf 1
#tar tvf /dev/rmt/0mn /etc/passwd

[Con O'Kelly]

Hi

Try using:

# mt -t /dev/rmt/0mn fsf 1
# tar xvf /dev/rmt/0mn

man make_tape_recovery has details on extracting single files from the tape archive.

Cheers
Con

[Jeroen Peereboom]

Alex,

for your information: a recovery tape consists of 2 'files' on the tape. The first is a bootable part, the second is a tar archive. That's why you need to skip forward 1 'file' before using tar (from the no-rewind device).

JP.

[Achilles_2]

JP,

I try but it still display an error:

root@hkdev:/ # mt -f /dev/rmt/0mn rew
root@hkdev:/ # mt -f /dev/rmt/0mn fsf 2
root@hkdev:/ # tar tvf /dev/rmt/0m
directory checksum error

Alex

[Kari Pannila]

>root@hkdev:/ # mt -f /dev/rmt/0mn rew
>root@hkdev:/ # mt -f /dev/rmt/0mn fsf 2
>root@hkdev:/ # tar tvf /dev/rmt/0m
>directory checksum error

Could you try the commands you were instructed to use (1 != 2) by Con and TG:

mt -f /dev/rmt/0mn fsf 1


BR Kari

[Michael Schulte zur Sur]

Hi,

since tar does recognize it as archive, it must be a bad tape. Have you tried on another machine?

Michael

[Lethuillier]

According to http://amor.cms.hu-berlin.de/~h0444idm/pub/sun/sun-trap3e ;

tar: directory checksum error

Cause

This error message from tar(1) indicates that the checksum of the directory and the files it has read from tape does not match the checksum advertised in the header block. Usually this indicates the wrong blocking factor, although it could indicate corrupt data on tape.

Action

To resolve this problem, make certain that the blocking factor you specify on the command line (after -b) matches the blocking factor originally specified. If in doubt, leave out the block size and let tar(1) determine it automatically. If that doesn't help, tape data could be corrupted.


-------------------------------------------
Are you using the recommended GNUtar, or standard tar?

Download GNU tar, run "configure", "make", then "make install" ;

ftp://alpha.gnu.org/gnu/tar/tar-1.13.93.tar.gz

[Jeroen Peereboom]

Alex,

as Kari says: you must do mt fsf 1 (one).
NOT 2 (two). You must skip (forward) one file, which is the bootable one. Then the tape is positioned just before the tar archive.

JP.