Recovering a file which is backedup using dd command

[A.Vishwanath_2]

Dear Gurus,

I have taken backup of 10 RAW LOGICAL VOLUMES using the below command
#dd if=/dev/vgsg/rt1.dbf of=/dev/rmt/0mn bs=8k
#dd if=/dev/vgsg/rt2.dbf of=/dev/rmt/0mn bs=8k
#dd if=/dev/vgsg/rt3.dbf of=/dev/rmt/0mn bs=8k

Now i want to restore the rt3.dbf file.Can u pls let me know the procedure for recovering the same.

TIA
Vishwanath.A

[Mark Grant]

Just reverse the "if" and "of" devices as in

dd if=/dev/rmt/0mn of=/dev/vgsg/rt1 bs=8k

[Bernhard Mueller]

Hi,

assuming you dd'ed all three files on a single tape (you used no-rewind device file) and want to restore ONLY the third tapefile, you would have to make sure to rewind the tape to the beginning, move forward two tapefiles, then extract the third tapefile.

mt -f /dev/rmt/0m rewind
mt -f /dev/rmt/0mn fsf 2
dd if=/dev/rmt/0mn of=/dev/vgsg/rt3.dbf bs=8k
mt -f /dev/rmt/0m rewind

Regards,
Bernhard

[T G Manikandan]

% dd if=/dev/rmt/0m of=/dev/ bs=

[Mark Grant]

oops, didn't read your post correctly. Bernhard has the correct answer to your question.

[T G Manikandan]

It this is a Oracle restore,you can also use the dbv (dbverify) utility to verify the restoration.

revert on further help!