fbackup with tape changer

[enrico.nic]

Hi

I recently bought a DDS tape changer from HP (DAT72 x 6), and I am still using "fbackup" for all our backup necessities.
From the fbackup man page, I learn that "Both DLT and DDS autochangers and libraries can provide unattended backups": ok, fine.
But the problem is, how can I change the tape through "fbackup" ?

Sorry for the trivial question.

Thank you

Enrico

[Peter Godron]

Enrico,
have you looked at these patches:
HP-UX 11.00 (PA-RISC): PHKL_29898
HP-UX 11.11 (11i V1 PA-RISC): PHKL_29899
HP-UX 11.23 (11i V2 IA-64) : PHKL_29900
HP-UX 11.11 PHKL-33425

Please also see:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1041825

[enrico.nic]

Let me explain better: "fbackup" is recognising the tape correctly through the device file, but sometimes during the backup the tape goes to its end and I need to change it "manually", through the appropriate utility (mtx).
After that I can tell fbackup to go on with its work: I simply wonder that "fbackup" can change the tape by itself, or through an external program.
All that, if I understand correctly the word "unattended" reported by the man page ..

Thank you

Enrico

[Peter Godron]

Hi,
in that case
see man fbackup , look for chgvol

If you search ITRC archive with
"fbackup chgvol"

Please see:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=111261

and James's answer in:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=11701

http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=225349

and many others.

[Bill Hassell · Accepted solution]

Not a trivial question at all. fbackup must ALWAYS use a config file (the -f option) for modern tape drives. Here is an example of a useful config file:

blocksperrecord 4096
records 64
checkpointfreq 4096
readerprocesses 6
maxretries 5
retrylimit 5000000
maxvoluses 200
filesperfsm 2000

By using this config file, you should see a significant reduction in the backup time.

One of the options in the config file is the keyword chgvol which defines a script that you must write. The script will use the environment variable $LIBRARY to define the changer's device file. Creating this device file is very dependent on the version of HP-UX you are using.

Next, you become familiar with the mc command to manipulate the changer. Now it sounds simple to switch tapes but there are no assumptions. So your script must unload the tape and place it in an unused slot. Then it must select the next tape and load it into the changer. So far, so good. But if your backup needs 3 tapes, the same script will be called and you can't unload the tape into the first slot. So the script needs stored logic in the form of a status file that keeps track of what is happening.

So the script can't assume anything -- it will be run every time fbackup runs out of tape and needs another volume. The script also should be initialized prior to the start of fbackup so the desired first tape is loaded (and no unknown tape was left in the changer).

So you'll need some scripting skills to handle all the possible conditions. The script's requirements would then be integrated into your current backup script.

[enrico.nic]

Thank you for your wonderful replies, the problem has been solved.

For the next persons that will read these messages, the right switches of the fbackup command are:
-f [device file]
-c [configuration file]

Enrico

[enrico.nic]

Problem solved, using a configuration file with the "chgvol" option and an external shell script.

Thank you again