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How to restore data from aix tar backup ?

Hi,

I have a aix (RS6000 Server) backup using tar on a DDS3 dat. I want to extract it on a Solaris system. But when i fire tar tvf /dev/rmt/1, it gives me "tarL: directory checksum error".

The tar backup taken on aix has a block size of 1024 and it is a compressed backup.

I have tried the following options :
tar tbvf 1024 /dev/rmt/1
tar tbvf 1024 /dev/rmt/1cbn
but it gives me the same error.
Does anyone have a solution to this problem ?

Regards,
Santosh Kini

jlevie

How was it compressed? Using hardware compresson on the DAT drive or software compresson on the AIX box as the data was written to tape? And if the later what compression tool?

There's a chance that the data is byte, relative to the Sun, on the tape. In that case you could use:

> dd if=/dev/rmt/1 conv=swab | tar xvf -

Now if software compression was done using compress you could do:

> dd if=/dev/rmt/1 | compress -d | tar xvf -

ecw

is the tar blocksize really 1024? if so, tar would read/write 512bytes*1024 ie. 512KB blocks. Try using a tar blocksize of 2 ie.
tar tvbf 2 /dev/rmt/1

santosh_kini

ASKER

Hi,
The data is compressed using hardware compression on the drive.

I tried using the options give by jlieve, but am getting the same error.

Also, i tried tar tvbf 2 /dev/rmt/1 but giving the same error.

Please help ...

Regards,
Santosh Kini

jlevie

Do you know what brand of DAT was used to write the tape? I don't know what one might find on an AIX system, but I do know that SGI has been known to use DAT drives that used a compression scheme not compatible with a standard DAT 2/3 drive.

Would it be possible to have the tape re-cut without hardware compression and a more normal blocking factor?

khaled022498

i used this command to retrive from NCR, it might be helpful.

dd if=/dev/rmt/1 conv=swab | tar xvf -

regards.

tfewster

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