MAXDB log volume size

[Former Member]

Hi

I am offloading the content in DMS_CONT1_CD1 table (size 320GB) from ECC system to Content Server based on Maxdb database using Program RSIRPIRL(note 389366). I have installed maxdb instance with 18 data volumes of each 18GB each on content server.

I am not sure how much size should I allocate for log volumes for 320GB database to avoid log full situation during content offload? Content sever will be running with LOG WRITING ON.

Unix team will take the backup with TSM tool after offload is completed.

Is it advisable to put database on LOG OVERWRITE MODE for large data transfer? Please advice.

[lbreddemann · Accepted solution]

> I am offloading the content in DMS_CONT1_CD1 table (size 320GB) from ECC system to Content Server based on Maxdb database using Program RSIRPIRL(note 389366). I have installed maxdb instance with 18 data volumes of each 18GB each on content server.

> Is it advisable to put database on LOG OVERWRITE MODE for large data transfer? Please advice.

Yes, you might use this feature for your data loading.

All you've to keep in mind here is that if the data load fails in between, you've to restore the content server database to the state before the loading started (there is no automatic resume-functionality available in the data loader).

A nice option to use here is the MaxDB Snapshot.

Just take a backup and a snapshot right before starting to load the data.

In case the database crashes in-between the data load and there is some physical damage to the data volumes, you can use the backup to restore the database.

In case of less severe problems, where you just want to start over the load, you can easily restore the snapshot (which is done in seconds) and restart the data load.

For the log volume size - most customers just go by one log volume of 1GB.

For a content server (and most other applications) that's enough by far and, due to the way MaxDB handles log data and volumes, there is no advantage in having multiple log volumes!

So stick with one as it keeps things easy.

regards,

Lars

[Former Member · Accepted solution]

Hi Lars

Thanks for reply. Before I start loading, there is no data in content server. Even if I restore the backup it will have no data.

The way the RSPIRIL program works it move each record from ECC to content Server and delete the record from ECC system.

In case of content server database crashing or volume damage, I would have lost data on ECC system as well as content server.

We have already moved content on ECC DEV/QAS to respective content Server, issue I had was log volume was full and then i have to change log mode to overwrite and carry on data load.

Because now I am doing PROD, i don't want take any chance with log full situation and database crash. Hence my aim to use maxdb backup/restore option after last savepoint in case of crash or any other problem .

what is MAXDB snapshot? how do you take it?

regards

asad

[Former Member · Accepted solution]

If you search for maxdb snapshot on SDN you will get the answer. The snapshots is used to freeze a specific state of a database and reactivate it again later.

If you are new to MaxDB I suggest you must read free MaxDB training material from http://maxdb.sap.com/training/

[lbreddemann · Accepted solution]

>

> We have already moved content on ECC DEV/QAS to respective content Server, issue I had was log volume was full and then i have to change log mode to overwrite and carry on data load.

>

> Because now I am doing PROD, i don't want take any chance with log full situation and database crash. Hence my aim to use maxdb backup/restore option after last savepoint in case of crash or any other problem .

Ok, just to set this straight.

A LOGFULL situation is in no way equal to or comparable to a database crash.

It's a situation that helps to prevent data loss.

Given that the correct reaction to LOGFULL in 99% of the cases is to take LOG BACKUPS and not to set log mode to overwrite.

> what is MAXDB snapshot? how do you take it?

There's documentation and examples available here in SDN and on [http://maxdb.sap.com/].

Read [this|http://maxdb.sap.com/training/expert_sessions/SAP_MaxDB_BackupAndRecovery.pdf] and you'll be a whole lot wiser about this topic.

regards,

Lars