use a tape on another system

[Charles Holland]

Working on a rp7410 with 2 cell boards and each cell board has to vPars. Only cellboard 0 has a tape drive. Is there ANY way that I can use it to backup, say vg01 from one of the other vpars? I've tried going through /net/private_lan_address/dev/rmt/0m tried exporting /dev/rmt from the OS with the tape on it... nothing!

Can this be done? If not why?

Thanks in advance.

[Sridhar Bhaskarla · Accepted solution]

Hi,

One way is to use fbackup. Look at -f option of fbackup in it's man page.

-Sri

[Charles Holland]

Thanks for the response, but when I try
fbackup -f private_lan:/dev/rmt/0m -i /tmp I get "could not open output file private_r3_prd:/dev/rmt/0mn" and I then have to answer no two times to get out of the process.

It seems so close but dies a death. I can't see a problem with the command but....

Regards

[Patrick Wallek]

If I recall correctly you must have remsh/rcp type capability between the two systems. If you don't have it you will need to set up a .rhosts file in roots home dir or a /etc/hosts.equiv file.

[Trond Haugen]

Maybe not a better solution but an option is the remsh|dd trick. Like:
tar cvf - . | remsh remote_system dd of=/dev/rmt/0m

Regards,
Trond

[Volker Borowski]

Hi,

you can use SAM, but you neet to setup the remsh access.

Make sure you have ".rhosts" in the home directory of User "root" on the machine with the tape. It should contain

ip_of_host_to_backup root

And have permissions "-rw-------".

Test it as root from host_to_backup with the command

remsh ip_of_host_with_tape ls -l /tmp

Should list the content of "/tmp" of the host_with_tape.

Go into SAM -> local backup and use a remote backup device.

Hope this helps
Volker

[Ralph Grothe]

Hi,

like Trond suggested, you can pipe the dump of any archiving or backup tool into a remote command on another host to write the dump to any appropriate device.

However, tar (especially if you're not using GNU tar) may not be the best choice if you have to care for e.g. large files.
Therefore I would take the tool which is best suited for your filesystem.

Since most of the filesystems on HP-UX by now are Veritas I would take their vxdump
(of course HP's fbackup should also work).
There's also no need for a trusted host relationship like .rhost.

If you don't mind the cryptographic overhead you could also use SSH.

E.g. as root

# vxdump -0f - /home|ssh remote_host 'cat >/dev/rmt/0mn'

If you need fancier blocking or conversion use dd instead of cat.

[Charles Holland]

We have made many discoveries since this thing started.
One.. for some unknown reason the operator had put a 90M tape into the HPsurestoredat40
drive. It will accept it but it won't write on it.
Once that was changed to a 120M tape the testing could be started all over again..

Second.. apparently because we have a san based tape attached we MUST use the 0mn device since the kernel parameter st_san_safe forces all tapes classified as "stape" to use the no rewind devices.

Patrick - the .rhosts and the /etc/hosts.equiv files were already in place.

Trond - an intereting idea that works unless you have sockets, or links, uderneath the point you are backing up. If you back up /tmp and it has a socket int it the socket doen't get backed up. You simply receive an error message about it saying "is not a file. Not dumped". There is a parameter that says for tar to "follow the symbolic link", but does that back up the link itself? Unknown.

Volker - Using your suggestion I was able to confirm that fbackup should work. When you go through sam, it collects your information and then uses fbackup to do the work.

Ralph - Some nice ideas.. had not known of xvdump before... may use it in the future.

FINAL Command was as follows using /tmp input

fbackup -f remote_host:/dev/rmt/0mn -i /tmp


Thanks to all.