retrieve the data in this situation

[Pinion]

Hello all,

We tried to import a HARP database yearly backup tape to HITDC but failed, it said blank tape after scan media.

We try to read the tape header using dd command, and it returned I/O error.
# dd if=/dev/rmt/3mn of=/tmp/dd_out bs=8192 count=30
dd read error: I/O error
0+0 records in
0+0 records out
#

We try another tape drive and do the import again and dd to isolate the problem to the media alone. The tape can be imported successfully, also can complete the dd command. This tape failed already in scan media operation, because header cannot be read.

Do you guy have any idea/solution to read the data out?

Thank you,

[Michael Steele_2 · Accepted solution]

HI

"...We try another tape drive and do the import again and dd to isolate the problem to the media alone. The tape can be imported successfully, also can complete the dd command. ..."

Usually this means the first tape is bad. However, you can try changing the block size in the dd command based upon values of 512.

There may also be more than one record on the tape. Use the mt command to move the tape ahead one record to try the second.

mt -t /dev/rmt/0mn fsf 1 (* move one record *)
mt -t /dev/rmt/0mn (* note the 0mn, n for no rewind, 0m is rewind *)