Tar: tape blocksize error

[boomerang]

Hi Admins,

I am trying to view the content of tape which contains ignite backup but getting error "Tar: tape blocksize error".Am i doing any thing wrong ? please help.

#ioscan -fnkC tape
Class I H/W Path Driver S/W State H/W Type Description
=====================================================================
tape 0 0/7/1/0.0.0 stape CLAIMED DEVICE HP C7438A
/dev/rmt/0m /dev/rmt/0mn /dev/rmt/c1t0d0BEST /dev/rmt/c1t0d0BESTn /dev/rmt/c1t0d0DDS /dev/rmt/c1t0d0DDSn
/dev/rmt/0mb /dev/rmt/0mnb /dev/rmt/c1t0d0BESTb /dev/rmt/c1t0d0BESTnb /dev/rmt/c1t0d0DDSb /dev/rmt/c1t0d0DDSnb

#tar -tvf /dev/rmt/c1t0d0BESTn
Tar: tape blocksize error

[R.O.]

Hi,

I think you have first to get rid of the first block in the tape, and then read the tar file:

# mt -f /dev/rmt/c1t0d0BESTn rew
# mt -f /dev/rmt/c1t0d0BESTn fsf 1
# tar -tvf /dev/rmt/c1t0d0BESTn

Regards,

[rariasn]

Hi:

# mt -f /dev/rmt/c1t0d0BESTn
fsf 1
# tar -tvf /dev/rmt/c1t0d0BESTn


http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1252842

rgs,

[boomerang]

R.O,

NOw I am getting the below error

#tar -tvf /dev/rmt/c1t0d0BESTn
Tar: blocksize = 0; broken pipe?

[boomerang]

I used "mt -f /dev/rmt/c1t0d0BESTn fsf 22"

then it worked.

Can any one explain why are skipping ahead ? what is that we are skipping ?

[R.O. · Accepted solution]

Hi,

You are skipping the tape boot area, which is 1 block for PA Risc ignite tapes and 22 for itanium...

Regards,

[Laurent Menase]

Hi
The trick to get the block size of a tape:

# mt -t /dev/rmt/c1t0d0BESTn rew
# mt -t /dev/rmt/c1t0d0BESTn fsf 1
# dd if=/dev/rmt/c1t0d0BESTn of=/dev/null ibs=128k obs=1 count=1
0+1 records in
10240+0 records out
-> this means that block size is 10240 ( it is always the size indicated as records out.

# mt -t /dev/rmt/c1t0d0BESTn rew
# mt -t /dev/rmt/c1t0d0BESTn fsf

# tar -tvbf 20 /dev/rmt/c1t0d0BESTn

20is for 10240 ( 512 bytes blocks)
the size should be 20 for the second record.

[boomerang]

Thanks for your suggestions and tips.Points awarded.