Life after ignite

[khilari]

Hi guys i took the ignite image and now i wanted to see the contents of it from the tape.
I used /0m for ignite and then i used tar and mt commands to see whats on the tape.
When i used tar i got the following errors. I tried using the /omn with tar in the hope that maybe the tape would rewind and start reading from the beginning but to no avail.

# tar -tvf /dev/rmt/0m
Tar: blocksize = 0; broken pipe?
# tar -tvf /dev/rmt/0mn
Tar: blocksize = 4
directory checksum error

then i used mt -t /dev/rmt/0m fsf 1 but it just returns a prompt back with nothing on.

Thanks.

[Pete Randall]

First of all, Ignite requires you to use the no rewind device file /dev/rmt/0mn, so you may not have successfully created your tape.

Secondly, in order to look at the contents you need to skip over the boot header before running your tar command:

mt -f /dev/rmt/0m fsf 1
tar -tvf /dev/rmt/0m


Pete

[Patrick Wallek · Accepted solution]

When you run a make_tape_recovery, Ignite creates 2 files on the tape.

The first is created with 'dd' and is the boot information. This is what allows you to boot from the tape.

If you want to see information from this area you can do:

# dd bs=8192k if=/dev/rmt/0mn of=/var/tmp/tape_boot.lif

This will run for a while, once it is done you can use the lif utilities against this file to see what it contains.

For example, to see what is included in the lif and when it was written to tape:

# lifls -l /var/tmp/tape_boot.lif

Or if you want to see the AUTO file echo'd to the terminal:

# lifcp /var/tmp/tape_boot.lif:AUTO -
(Note that there is a between the O in AUTO and the - .)

The 2nd file on the tape is created by pax, and by default is a 'tar compatible' archive. This behavior can be changed with the '-m' switch and can be either '-m tar' or '-m cpio' depending on your preference.

To see the contents of this file you should do:

# mt -f /dev/rmt/0mn rew
To rewind the tape

# mt -f /dev/rmt/0mn fsf 1
To space forward past the boot area

# tar -tvf /dev/rmt/0mn

To list the files on the tape. Pay special attention to the file paths. Note that none of them have a leading '/'. This is important if you ever want to restore a single file from this archive.

To restore /etc/hosts for example:

# cd /
# mt -f /dev/rmt/0mn rew
# mt -f /dev/rmt/0mn fsf 1
# tar -xvf /dev/rmt/0mn etc/hosts

Note that I ommitted the '/' in front of 'etc' in the file name. If you don't do this tar will not be able to find the file.

Good luck.

[khilari]

I am making the ignite again on the same tape with /omn, so when u say
(Secondly, in order to look at the contents you need to skip over the boot header before running your tar command:). What does that mean ?.

[Pete Randall]

It means just what it says. There are two portions to an Ignite tape: the boot header which allows you to boot off the tape and the actual archive. Patrick does a nice job of explaining it above.


Pete

[Steven E. Protter]

Its a great procedure, same as I got years ago out of the HP Response Center.

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