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Logical Log Backup Under Informix

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Amit Dixit_2
Regular Advisor

Logical Log Backup Under Informix

Hi,
I am running Informix 9.40 on my HP-UX 11.23
I have configured LTAPEDEV to PATH_TO_MY_DISK

Now After few days I am getting error
"Logical Logs are full replace tape and
press enter to continue..."

What should I do ?
What is the best way to deal with logical
logs and can they be backed up on Hard Disk
and how to clean them.

Thanks & Regards,
Amit
4 REPLIES
Rainer von Bongartz
Honored Contributor

Re: Logical Log Backup Under Informix

First try to do an manual logical log backup using

onbar -b -l

Then configure your ALARMPROGRAM to do automatic logical log backup whenever a logical log is full

Regards
Rainer
He's a real UNIX Man, sitting in his UNIX LAN making all his UNIX plans for nobody ...
Amit Dixit_2
Regular Advisor

Re: Logical Log Backup Under Informix

Hi,
Please can you briefly descibe the LOGGING
process and where are they backed up when i
will be giving "onbar" what is the physical
location of the same.

Please help me with this I am also following
the document and want to design permanent
solution for the same.

Thanks
Amit
Rainer von Bongartz
Honored Contributor
Solution

Re: Logical Log Backup Under Informix

Amit,

Informix stores logical log entries in logfiles
given by the $ONCONFIG parameters

LOGFILES
LOGSIZE

when one of this logfiles is full, Informix switches to next log.

To empty the files you have to backup them. This could be done to the file system or tapes. If you dont want to keep them you might even backup them to /dev/null.
(LTAPEDEV).

To have an automatic backup you should configure an alarm program

ONCONFIG parameters (i.e.)
ALARMPROGRAM /informix.prod/etc/alarm.sh

in /informix.prod/etc/alarm.sh there sould be something like

case $EVENT_CLASS
in
23)
onbar -b -l 2>&1 >> /dev/null
EXIT_STATUS=$?
;;

whenever a logical log file is full, INFORMIX generates alarm 23 and starts the ALARMPROGRAM. this shell script then backs up the logical with using onbar .

Regards
Rainer





He's a real UNIX Man, sitting in his UNIX LAN making all his UNIX plans for nobody ...
Brian Butscher
Frequent Advisor

Re: Logical Log Backup Under Informix

Amit,

It sounds like the the logical logs are not being backed up to the PATH_TO_MY_DISK or the filesystem where PATH_TO_MY_DISK is full. If the filesystem is full, you will need to copy those files to tape or to another disk. If the logical logs have not been backed up, which sounds like the configuration for LTAPEDEV isn't working so those logs should be backed up to tape. If you are not using ontape -c for automatic backup of your logical logs then you need to setup the log_full.sh to run ontape -a. You can also run ontape -a from the command line which will backup the logical logs to your back up device immediately and will free up your logical logs. The -c is for continuous backup of your logical logs.
The logical log backup must use the same backup utility as the physical backup;if you use ontape for your backups then you must use ontape -a or -c to backup your logical logs, if you use onbar for your physical backups then you must use onbar -b -l or onbar -l -c (for the current log), since you are running IDS 9.4. Don't set your LTAPEDEV to /dev/null as you will only be able to restore your physical backup(s) and not any logical logs. If you have to restore to the most current state of your database or a point-in-time (as with the case using onbar), the logical logs are used to replay all the tranactions up to the point the database went down.

Brian