Content Server backup files

[Former Member]

Hello,

I am using Content Server with MaxDB 7.6 and doing a daily backup and log backup via dbmcli (SAVE WARM).

In the backup folder, I saw two files saved daily which is ContentServer.bck (DAT_000000293) and

ContentServer_log.bck.278 (LOG_000000278).

Can I confirm that in the event of a crash, I only need to restore the most recent files i.e ContentServer.bck and ContentServer_log.bck.278?

Thank you.

Edited by: Steven888 on Jul 8, 2010 11:51 AM

[lbreddemann · Accepted solution]

>

> Hello,

>

> I am using Content Server with MaxDB 7.6 and doing a daily backup and log backup via dbmcli (SAVE WARM).

> In the backup folder, I saw two files saved daily which is ContentServer.bck (DAT_000000293) and

> ContentServer_log.bck.278 (LOG_000000278).

>

> Can I confirm that in the event of a crash, I only need to restore the most recent files i.e ContentServer.bck and ContentServer_log.bck.278?

"In the event of a crash" - Why would you restore in this case?

A crash means: the database kernel process abort and cannot finish the current transactions.

The data volumes will then contain inconsistent data (which they do basically ALL the time!).

The next time you restart the database, it will automatically find the last savepoint and recover all transactions that were executed since then (based on the information in the LOG AREA).

All this happens fully automated without any DBA interaction (it's called 'crash recovery').

So "in the event of a crash" you typically don't need a backup at all.

regards,

Lars

[Former Member · Accepted solution]

Sorry if I didn't explain clearly what I wanted to know.

I was referring to a hardware crash where the files are not available and I need to perform a restore.

For example, my daily backup files are as below:

July 6

ContentServer.bck (DAT_000000291)

ContentServer_log.bck.276 (LOG_000000276)

July 7

ContentServer.bck (DAT_000000292)

ContentServer_log.bck.277 (LOG_000000277)

July 8

ContentServer.bck (DAT_000000293)

ContentServer_log.bck.278 (LOG_000000278)

My understanding is ContentServer.bck refers to the full backup while ContentServer_log.bck.278 is the log backup.

If I need to restore, I just need to restore the latest backup which is ContentServer.bck and ContentServer_log.bck.278?

[lbreddemann · Accepted solution]

> I was referring to a hardware crash where the files are not available and I need to perform a restore.

> For example, my daily backup files are as below:

>

> July 6

> ContentServer.bck (DAT_000000291)

> ContentServer_log.bck.276 (LOG_000000276)

>

> July 7

> ContentServer.bck (DAT_000000292)

> ContentServer_log.bck.277 (LOG_000000277)

>

> July 8

> ContentServer.bck (DAT_000000293)

> ContentServer_log.bck.278 (LOG_000000278)

>

> My understanding is ContentServer.bck refers to the full backup while ContentServer_log.bck.278 is the log backup.

>

> If I need to restore, I just need to restore the latest backup which is ContentServer.bck and ContentServer_log.bck.278?

Simple answer: yes - just apply the most recent full data backup plus all Log-Backups that had been created after this backup.

When you start the recovery wizard in DBA Studio or DBM GUI it will automatically determine and preview what backups are required for the recovery.

You can also simulate this case by using the "Check Recovery" functionality. This will just read the backup data from the backup files but won't write it back to the database instance.

More complicated answer:

You've got backups taken into file system and you got a hardware crash that makes your file system unusable... how many backups do you have then?

Besides that: as you seem to have only few changes in your database, you only have just one log backup per day.

This means the remaining log informationen is stored in the LOG AREA which would be lost in a total disaster case.

To prevent this, I propose to use the time-based automatic log backup and take a log backup, say every two hours.

You'll end up with more log backups to recover then, but you won't loose a days worth of data.

As always: make sure to check the documentation and the expert sessions available at http://maxdb.sap.com/ !

regards,

Lars

[Former Member · Accepted solution]

Thanks Lars, that was helpful.

[Former Member]

In order to get back to the last transaction you will need a full backup and logs created after that full backup.

This is not different from other database backup routines.