tar & dd problem

[xertusit]

Hi fellas,
i've backupped io2 file via tar. Now I want extract io2 not via tar but via dd. The operating system returned me these error:
# tar tv
-rw-r--r-- 0/1 36567531 Feb 9 12:18 2006 io2
drwx------ 0/0 0 Feb 6 15:50 2006 lost+found/
# dd if=/dev/rmt/0 of=/dev/null
read: Not enough space
0+0 records in
0+0 records out

Of course the file system where I restore the io2 file have the right space available.

Thanxs,
Massimo

[Robert-Jan Goossens_1]

Massimo,

where is the file io2 ?

is this a typo?

# dd if=/dev/rmt/0 of=/dev/null
# ll /dev/rmt/0

Robert-Jan

[Devender Khatana]

Hi,

The file backup up using tar can not be extracted using dd. dd does block by block copy and it below file level.

Use tar itself to extract the file

#tar -xvf io2 .

HTH,
Devender

[xertusit]

The file /dev/rmt/0 is a link to /dev/rmt/0m

[Luk Vandenbussche]

Hi,

If your file is on a tape you must use /dev/rmt/0m

[xertusit]

The /dev/rmt/0 is a link to /dev/rmt/0m.

[paolo barila]

# mt rew

# tar xvf /dev/rmt/0mn io2

[xertusit]

I don't interested if the data into dds data are archived via tar or frecover...I need to understand the way to dump a dds dat into a temporary file system via dd.

Massimo

[Zinky]

Brion - Peace:

Try this:

mt -f /dev/rmt/0mn rew

Then, the following will extract the first "file" (be it tar, fbackup, dump, vxdump format) on the tape:

dd if=/dev/rmt/0mn of=/somefs/tapefile.1 bs=10240

Then test the recovered "raw" file with:

tar tvf /somefs/tapefile.1


Note: if the "tar file" on the tape was backed up with no blocking factor -- its default will be 20 (@ 512bytes). That is why you need to specificy it in your dd command.

If you've multiple "files", then just continue usingwith yur dd'd noting the bllock size of your "files". You may also use the "mt asf/fsf" file positioning commands if you want to go to a particular "file" on your tape.

Hope this helps.

[xertusit]

There was a bs wrong...I've tried with 128k and now it's all ok!!

Massimo