MAXDB Force Log Backup

[Former Member]

Hi All,

I am facing an issue in generating the Log backup. The scenario is given below:

1. Most of the users will not work on the system. If we can see the previous data, for one week only 20 MB of log will be written.

2. And I want to enable time controlled Log Backup on this system. So I have followed the note 869267 and enable the interval using the command -- autolog_on <medium> INTERVAL <time in secs>.

3. Now I am not able to get the logs backed up for every 15 minutes.

So Please can anyone of you tell me how to forcefully write the log for every 15 mins.

Best Regards,

GK.

[lbreddemann · Accepted solution]

> 1. Most of the users will not work on the system. If we can see the previous data, for one week only 20 MB of log will be written.

> 2. And I want to enable time controlled Log Backup on this system. So I have followed the note 869267 and enable the interval using the command -- autolog_on <medium> INTERVAL <time in secs>.

> 3. Now I am not able to get the logs backed up for every 15 minutes.

Why is this?

When using an interval of 900 seconds, the log backups should be taken every 15 minutes.

Are there any error messages in the KNLDIAG file about failing backups?

Have you checked, whether there is actually log data that can be backed up after the 15 minutes interval?

About what version are we talking here?

regards,

Lars

[Former Member · Accepted solution]

we are using the system for PLM purpose. So I am not sure that there will be enough log written to take backup every 15 minutes. And also I have checked knldiag file there were no error messages related to log backup. That is why i mentioned the log that got generated after a week will be around 20MB. My concern is somehow we need to force fully do the log backup for every 900 secs.

Is there any other parameter or message that tells the log backup is triggered for every 15 mins.

Regards,

GK.

[lbreddemann · Accepted solution]

Hi GK,

if there are no log information to be backed up, then there won't be a log backup.

What would it be usefull for?

Even if you would manually try to create a log backup, you'll get a "no more log to save" message and no log backup file.

Sofar, it does not look like something is not working here.

regards,

Lars

[Former Member · Accepted solution]

Hi Lars,

My concern is, irrespective of whether users work or not on the system, it has to generate a log for every 15min. I meant to say force log backup. The same we have enabled on Oracle Database and it is working fine for some systems like Enterprise Portal. Earlier In Enterprise portal, the logs used to get generate for 2 to 4 hrs. After enabling the time controlled on Oracle database the logs are forcefully get generated for every 15 mins. We want the same feature to be enabled on MAXDB database too. Please tell me If we have any other extra parameter that needs to be set to enable this feature.

Regards,

GK.

[lbreddemann · Accepted solution]

Hi GK,

> My concern is, irrespective of whether users work or not on the system, it has to generate a log for every 15min.

Yes, I got that the first time

Anyhow, for MaxDB this is a nonsense operation. If there are no changes to the database then there are no log entries and thus no log to be backed up.

We never "make up" entries there and we don't copy data/redo files during backup.

We save the data we have to new files

> The same we have enabled on Oracle Database and it is working fine for some systems like Enterprise Portal. HI GK,

And that is a nice idea for Oracle - but just because of the way Oracle redo log files and the redo log archiving works.

For Oracle - at least for the user managed backups (you know, BEGIN BACKUP/END BACKUP, not RMAN - you want to perform log file switches to have a kind of "sync"-point between log and data files.

That concept of redo log files and the switches between them just don't exist with MaxDB.

For MaxDB the log area is a rather contiguous space where we put in our log data.

On backup time we write out portions of it to the backup medium (the portions are called LOG BACKUP SEGMENTS).

We don't need to "finish" one file of the log area to be able to do that.

And we always "know" at what position in the log area our most current entry resides - thus we don't need the extra "sync" point.

You may want to read more about how logging works in MaxDB [>here<|http://maxdb.sap.com/training/internals_7.6/logging_EN_76.pdf].

To close, your current setup is doing exacty what you want to archive.

You don't want to get an empty file every 15 min. but you want to make sure that - should there be any changes to the database - that the log entries for those are backed up within the following 15 mins.

That's what you got here.

Cheers,

Lars