br_backup won't re-use LTO

[David Connolly]

Hello all,

My automated backup on an 11i system is failing with the following error:
fbackup(1004): session begins on Thu May 29 04:00:00 2003
fbackup(1517): /net not backed up - 'n' option (NFS) not specified
fbackup(3203): volume 1 has been used 100 time(s)
fbackup(3204): volume used more than maximum, do you want to use this volume anyway?
fbackup(3004): writer aborting
fbackup(1002): Backup did not complete : Reader or Writer process exit


My solution is to use fbackup with the -y flag to answer "Yes" to all inquiries. However, I don't particularly want to edit the br_backup script, as a patch or upgrade will overwrite. I notice br_backup passes $hidden_option to fbackup, but cannot see where it is set.

Any ideas? Or should I just bite the bullet and edit the script?

Thanks in advance

Dave

PS - I need to use the tape more than 100 times, because LTO tapes are costing me around $200 each!

[James R. Ferguson · Accepted solution]

Hi David:

TO correct this, simply 'tar' a file to the tape in question. When 'fbackup' is run again, it will treat the tape as one it has never used.

Regards!

...JRF...

[Leif Halvarsson_2]

Hi,
One solution is to copy the script and edit the copy. Then use this "custom" script for your backup jobs.

[James R. Ferguson]

Hi (again) David:

Also, I just remembered, that you can define the 'maxvoluses' in the 'config' file used by 'fbackup'. The default value is 100 which would apply in the absence of any configuration file (bad). See the man pages for 'fbackup' for more information.

Regards!

...JRF...

[Massimo Bianchi]

Hi,
Create a configuration file called config in the directory /var/adm/fbackupfiles

Inset in it the line
maxvoluses NUMBER_OF_TIMES_YOU_WANT


then call fbackup with the option
-c /var/adm/fbackupfiles/config.


For other specs, have a look at man page.

HTH,
Massimo

[James R. Ferguson]

Hi David:

One more comment. If you are not using a 'config' file with 'fbackup' you are going to get very poor backup performance.

In the absence of an explicit configuration file ('-c config'), default values are provided for the 'fbackup' (and any subsequent 'frecover' session. See the 'fbackup' man pages). These defaults are archaic A better set of parameters look something like these:

blocksperrecord 256
records 32
checkpointfreq 1024
readerprocesses 6
maxretries 5
retrylimit 5000000
maxvoluses 200
filesperfsm 2000

These parameters are recorded onto the actual backup tape and are thus used for a 'frecover' session too.

Checkpoint records allow the salvage of a backup when a bad tape spot is detected, since the records contain information about the file being backed up. The 'filesperfsm' parameter controls the frequency with which Fast Search Marks (FSM) are written. Both checkpoint and FSM records affect performance. FSMs take a tape drive out of streaming mode thereby adding to backup time. Conversely, however, FSM???s improve the time it take to recover a file from tape.

In general, if your backup consists of a high proportion of small files, increase the value for 'filesperfsm'. If your backup consists of a high proportion of large files, then decrease the 'filesperfsm' value.

Regards!

...JRF...

[David Connolly]

Thanks James,
br_backup actually creates a fbackup_config file in /etc/sam/br with the default values in it if none exists alreadu - so it actually does use a config file.

I just modified this file & set maxvoluses to 1000.

Thanks everyone.

Dave