howto determine DDS tape format

[Andrew Beal]

Hi,

I have been asked to do a restore from about 2000. There is no documentation on the backup procedure then, and all I have is a DDS3 tape...

How can I tell what type of medium format the tape is in i.e. tar, cpio, data protector, fbackup etc...

Also, this host is connected to SAN tape library, and "no tape rewind" kernel parameter is set. Would this effect my ability to read tar etc... How do I rewind a DDS tape once this kernel parameter is in place?

Thanks in advance,

Andrew

[sajeesh_3]

hi andrew,

don't know how to check/verify the type of the data written, but i'm sure, mt command could be of a great help to you...

mt status will give you atleast the tape drive and the catridge information.

you can rewind a dds tape by

mt rew
specify the device file for tape with the -f option

with regards
sajeesh

[Rajesh D L]

Hi Andrew,

Try to read the tape using different utilities like tar, cpio, fbackup etc. You wont have to spend much time for this, because the frequently used utilities are hardly 3 or 4. "no tape rewind" parameter will not affect the ability to read tar backup.

regards,
RDL.

[Joseph Loo]

hi,

to check what type of tape your tape driver may take:

# ioscan fnC tape
u may see the following type of device names
/dev/rmt/0m
/dev/rmt/0mb
/dev/rmt/0mn
/dev/rmt/0mnb
/dev/rmt/c3t3d0BEST
/dev/rmt/c3t3d0BESTb
/dev/rmt/c3t3d0BESTn
/dev/rmt/c3t3d0BESTnb
/dev/rmt/c3t3d0DDS
/dev/rmt/c3t3d0DDSb
/dev/rmt/c3t3d0DDSn
/dev/rmt/c3t3d0DDSnb

to rewind your tape:
# mt -f rew

regards.

[Andrew Beal]

Thanks for this.

I will play around with those utilities. Also I got the tape to rewind!! I must have been confused from some output in dmesg saying I cannot rewind the tape cause of that kernel parameter... After trying the above commands, the dmesg errors did not increase, and the tape rewound!

But any more info on how to determine media type would be greatly appreciated!

Andrew

[Suresh Patoria]

Hello,

Check the staus of the media

#mt -t /dev/rmt/Xmn status

Thanx

Suresh

[Joseph Loo]

hi,

as suresh has mentioned:

# mt -f status

the -t option is consider obsolete in some ux version.

regards.

[Shaikh Imran]

Hi,

check this out
attached doc
Regards

[Andrew Beal]

awsome! using dd to read the first 1024 bytes was cool. It told me the format of the tape from the header... example output below...

#dd if=/dev/rmt/5mn of=/var/opt/sw/omni/crap/crap.5m bs=1024

#strings ./crap.5m

VOL1OMNI-2-[HP OmniBack II v1.0 ]D%-3310000003 [HP OmniBack II v1.0 ]1nNBSABCD
0ac40b87:3e032298:645c:0001
classakl_13
classakl

Well this gives me some place to start. Thanks all for your help!

Andrew

[Andrew Beal]

OK, I now have another question... It appears this backup was created on a AIX box using the aix "backup" command...

I have tried using the hpux "restore" command but that is only used for restoring tapes created via "dump" or "rdump".

I also tried cpio -itcv < /dev/rmt/3mn but had no joy with that either...

I have no AIX experience, and would appreciate it if any has got an idea on how I can restore this data, and list the contents of the tape on HPUX, as we dont have an AIX box anymore...

Thanks in advance,

Andrew

[Bill Hassell]

Luckily, this is a backup from a commercial quality backup program (HP's Omniback product) so the header is quite readable. The same is true for fbackup. tar,cpio,pax, etc just start with binary volume data. You'll need a copy of Omniback to read this tape (it's a commercial product).

Another trick to ID a tape is the file command. It reads a few bytes from any file (or device file) and then goes through several dozen tests to find a unique signature (a magic number). file is ideal for binary file identification.

[Andrew Beal]

Oh, and btw... I am using a different tape now, so disregard the omniback stuff in the tape header... I will post the new header from the new tape...

#strings crap.3mn

by name
by name
root
/var/backup/log/tape.txt
yname.c
Backup of classakl started at Fri Dec 7 21:55:01 NZST 2001 to /dev/rmt0.1
Backup of /var/backup/log/tape.txt /prod /u/appl /home / /usr /var /tmp using backup and savevg commands

[Bill Hassell]

It is very likely that the AIX backup tape format is proprietary to IBM (like fbackup is for HP-UX). You'll need an AIX box to restore the tape (and convert it to an interchangeable format like tar)

[V. Nyga]

Hi Andrew,

with 'backup' - it also could be a backup tape written by SAM - Backup and Recovery!

It's a try ...

Volkmar