UNIX for Dummies Questions & Answers

I was recently given the responsibility of the unix box at our work. Without much training, I now have to go back and restore a file from tape. I'm having some trouble with it. I'm getting an error with the blocksize.

The part of the script that does the tar looks like this:

tar cvfX /dev/rmt/0n backup_exclude_file /* /LAST_FILE >> /data/unix_backup.log

It doesn't seem like the script specifies the blocksize? Am I wrong?

This is the commands I executed to do the restore:
mt -f /dev/rmt/0 status
mt -f /dev/rmt/0 rewind
mt -f /dev/rmt/0n fsf 1
tar xvf /dev/rmt/0 /data/exports/files/C_XMDL.dmp.Z

It gives me this error:
tar block size =1
directory checksum error

I was told to try a blocksize of 2000, but it seems like the command just hung. I had to kill it after 2-3 hours.
This is what I excuted for that:
tar xvfb - 2000 /dev/rmt/0 /data/exports/files/C_XMDL.dmp.Z

We are using a Dell SDLT 320 Powervault 110T

I'd appreciate any suggestions.

mt -f /dev/rmt/0n fsf 1

why did you do that? You might try it again without that command.

My notes from the previous Unix admin told me to do that because, there was a previous tar done before that. I did not include it in the post.

The first tar in the script was
tar cvf /dev/rmt/0n /restore /etc/passwd /etc/shadow /etc/group /export/home/oracle >> /data/unix_backup.log

He told me it's because he wanted the password file and oracle profile backed up at the beginning of the tape for disaster recovery purposes.

I'm sorry. I did not get a checksum error:
I just got
tar: blocksize = 0

That's it'. It happens right away, and it did not restore the file.

tar xvfb - 2000 /dev/rmt/0 /data/exports/files/C_XMDL.dmp.Z

That command is wrong and that is probably your problem. It instructed tar to read from standard input. Use:

mt -f /dev/rmt/0 rewind
mt -f /dev/rmt/0n fsf 1
tar xvfb /dev/rmt/0 2000 /data/exports/files/C_XMDL.dmp.Z

Thank you so much for replying and trying to help me out.

I tried the command you provided. I did them exactly in the order you provided. However, I still got the same error:
tar: blocksize = 0

I don't know if this makes a difference, but I believe I forgot to mention was OS and level I was using.
I'm using Sun Solaris. 2.9