BR*Tools Command Line on AIX

[Former Member]

Hi Everyone,

I would like to ask for your assistance on how can I solve our backup issue on our SAP Prod Server (running on an AIX Server). We usually do an offline database backup every weekend scheduled on tcode DB13. We backed up the database to LTO3 tape drive. The backed up database reached 750GB. We were able to backed up it on LTO3 tape cartridge (which has a native capacity of 400GB and compress capacity of 800GB) using the hardware compression of tape drive. My questions are, if this database backup exceeds the tape compress capacity of 800GB, what will happen to our offline database backup scheduled on DB13? Do we have other ways to perform the offline database backup other than using DB13?

Please help me.

Regards,

Ronald

[Former Member · Accepted solution]

Follow up question: Can we use the brbackup through command line on AIX?

[former_member524429 · Accepted solution]

Hi,

Can we use the brbackup through command line on AIX?

Yes.

Please refer this SAP Note 13550 - Using BRBACKUP and BRARCHIVE (section parallel Backup).

If you are having Tape Library with multiple Tape Drives, then u can specify the individual tape addresses in tape_address and

tape_address_rew parameters of the profile init<DBSID>.sap.

Regards,

Bhavik G. Shroff

Edited by: Bhavik G. Shroff on Feb 16, 2010 1:38 PM

[markus_doehr2 · Accepted solution]

> Follow up question: Can we use the brbackup through command line on AIX?

Sure.

Just use brtools, select the menu entries as you want just before the last "go", write down the command line displayed and schedule it.

Markus

[Former Member · Accepted solution]

Hi Bhavik and Markus,

Thanks so much for the info. How about if the backup exceeded the capacity of the tape cartridge, does it prompts you to mount the next tape or it will terminate the backup? We only have a single external tape drive without changer or robot to use the automatic tape management.

Regards,

Ronald

[former_member524429 · Accepted solution]

Hi,

If tape_copy_cmd = cpio is set in init<DBSID>.sap, then please refer this[ useful link|http://help.sap.com/saphelp_nwmobile71/helpdata/en/47/3b65962517220ae10000000a155369/content.htm].

Regards,

Bhavik G. Shroff

[Former Member · Accepted solution]

Hi Bhavik,

You mean, if the value of tape_copy_cmd is set to cpio, we can perform the continuation backup? This will require us to have a console to execute the brbackup command in interactive mode? I mean, you will be prompted to unmount the first tape and mount the second tape and press enter to continue?

Regards,

Ronald

[Former Member · Accepted solution]

Hi,

if the backup exceeded the capacity of the tape cartridge, it will eject the current tape and will wait for next tape to be inserted.

But this will be a manual process to change the tape, if you have single tape drive...

Better you may think about tape library for large backup...

Regards.

Rajesh Narkhede

[Former Member · Accepted solution]

Hi Rajesh,

Its ok with us to perform the manual unmount/mount of tape cartridge since we don't have budget yet for the new tape library. Without changing any parameter setting on the init<DBSID>.sap profile, it will automatically eject the tape after exceeded the capacity of first tape? Does this also applicable on DB13?

[former_member524429 · Accepted solution]

Hi,

it will automatically eject the tape after exceeded the capacity of first tape? Does this also applicable on DB13?

Yes It will do.

But While restoration , you will have to use all correct Tapes which you used for such serial backup. e.g. The cpio continuation tape is not u201Cvisibleu201D for BRBACKUP or BRARCHIVE, that is, it is regarded as one logical tape together with the first one.

Regards,

Bhavik G. Shroff

[Former Member · Accepted solution]

Hi Bhavik,

You mean, we do not need anymore to execute the full offline backup in command line because serial backup is also applicable using the DB13? We need only to wait when is the time the backup process eject the 1st tape and insert the 2nd tape?

Regards,

Ronald

[Former Member · Accepted solution]

Hi Bhavik,

You mean, we do not need anymore to execute the full offline backup in command line because serial backup is also applicable using the DB13? We need only to wait when is the time the backup process automatically eject the 1st tape and manually insert the 2nd tape to continue the backup?

Regards,

Ronald

[former_member524429 · Accepted solution]

Yes.

But it is not a recommended way to perform Backup operation.

Some problems may come during Restoration from such Tapes, if you do not remember the Tape Set and provide another Tape.

As an alternative, You can perform compressed Offline Backup of your Database to save Tape space.

Regards,

Bhavik G. Shroff

[Former Member · Accepted solution]

Hi Bhavik,

Better to perform the database backup on command line right? If we do a compressed offline backup, it will take more time to finish the backup aside from hardware compression that we enabled already? Therefore, the backup will be compress twice.

Regards,

Ronald

[former_member524429 · Accepted solution]

Hi,

Better to perform the database backup on command line right?

DB13 is just providing a view. Ultimately the DB BACKUP and other DB13 Jobs are performed on command line in back-end. You can also execute the offline backup at OS level using BRBACKUP command.

If we do a compressed offline backup, it will take more time to finish the backup aside from hardware compression that we enabled already?

I forgot to see that "ur existing Tape device is supporting H/W Compression", then always use hardware compression while performing DB Backup.

Regards,

Bhavik G. Shroff

[Former Member · Accepted solution]

Hi,

Yes, it will be better to backup from the command line..

One another advantage is that, you can see the progress of your backup in terminal windows. Otherwise everytime you will need to go through the current backup log file to see the progress...

I will suggest, that you should maintain the sequense of your tapes by marking the numbers on the tape.

I Hope, you are aware of BRBACKUP command line parameters..

Regards.

Rajesh Narkhede

[Former Member · Accepted solution]

Hi Everyone,

Thanks so much for all your help. I'm sorry, I'm new on this commands. But, based from my understanding, correct me if I'm wrong. Using oracle admin user, I have to initialize the tapes I'm going to used like the command below:

brbackup -p init<DBSID>.sap -i -n 2 -v <volume_name>

Then, I will perform the offline backup using the command below:

brbackup -p init<DBSID>.sap -d tape -v <volume_name> -t offline -m all -k no -e 0

Is this all correct?

Regards,

Ronald

[former_member204746 · Accepted solution]

in most cases, Oracle database, when backed up using BRBACKUP on LTO tapes usually compresses 4:1 easily.

So, you should be able to backup up to 1600GB on that 400GB tape.

that 800GB value is just a generic value, this changes depending on what data is being backed up.

[Former Member · Accepted solution]

Hi Eric,

We have an IBM LTO3 tape drive with IBM LTO3 tape cartridge. Based from the tape cartridge specification, native capacity is 400GB and compress capacity is 800GB. We used hardware compression. Based from my understanding, it can only stored data to LTO3 tape cartridge up to 800GB (compressed) only. Is there a possibility that the tape cartridge will be able to accommodate more than 800GB of data?

Regards,

Ronald

[former_member204746 · Accepted solution]

Yes, this is what I told you.

400GB is the only value you can trust.

800GB is just a mere evaluation of how much it can compress. Do not trust that value.

If you backup ZIP files, you will backup only 400MB of ZIP files

but, if you backup TXT files, you will be able to backup to to 4000GB because compression rate of TXT files is usually 10:1.

Oracle DB usually compressed 4:1... up to 1600GB (400x4=1600).

[Former Member · Accepted solution]

>

> Oracle DB usually compressed 4:1... up to 1600GB (400x4=1600).

Hi Eric,

Is this compression is on the Oracle DB level or in the hardware (tape device) compression?

I would like to go back to my original request for assistance. I posted this question for us to know when will the backup will require a 2nd tape cartridge to insert. I would like to ask for your assistance if the command below will asked/prompted you to load 2nd tape drive.

brbackup -p init<DBSID>.sap -d tape -v <volume_name> -t offline -m all -k no -e 0

For example, we know that our backup will exceed one tape cartridge capacity, do I need also to perform tape initialization for two tapes before executing the offline db backup?

Thanks so much for helping me.

Regards,

Ronald

[Former Member · Accepted solution]

>

> Oracle DB usually compressed 4:1... up to 1600GB (400x4=1600).

Revised .....

Hi Eric,

Is this compression is on the Oracle DB level or in the hardware (tape device) compression?

I would like to go back to my original request for assistance. I posted this question for us to know when will the backup will require a 2nd tape cartridge to insert. I would like to ask for your assistance if the command below will asked/prompted you to load 2nd tape cartridge. Using oracle user:

brbackup -u / -c -p init<DBSID>.sap -d tape -v <volume_name> -t offline -m all -k no -e 0

For example, we know that our backup will exceed one tape cartridge capacity, do I need also to perform tape initialization for two tapes before executing the offline db backup?

Thanks so much for helping me.

Regards,

Ronald

[former_member524429 · Accepted solution]

Hi,

this compression is on the Oracle DB level or in the hardware (tape device) compression?

If compress=yes is used then Software compression of files will take place during backup. If compress=hardware (which is recommended in you case), then the compression responsibility will be of the Tape Device Drive, which support Hardware compression. The Hardware compression setting should be enabled on that Tape Device Drive.

when will the backup will require a 2nd tape cartridge to insert. I would like to ask for your assistance if the command below will asked/prompted you to load 2nd tape cartridge. Using oracle user:
brbackup -u / -c -p init<DBSID>.sap -d tape -v <volume_name> -t offline -m all -k no -e 0

The consequences depend on the copy program used by BRBACKUP. such as CPIO , DD

DD always generates an error message when it reaches the end of the tape. The backup process terminates with an error "I/O error". Where as in serial Backup using CPIO, CPIO requests a CPIO continuation volume and the backup process continues.

do I need also to perform tape initialization for two tapes before executing the offline db backup?

With CPIO Tape continuation, Since no label check takes place for the continuation volume, no need to initialize the 2nd Tape as 2nd Tape will be overwritten at all. So do not use any other initialized Tape volumes.

Regards,

Bhavik G. Shroff

[former_member524429 · Accepted solution]

Hi,

tape_size plays an important role to avoid such physical Tape-end situation and for the optimal distribution of backup files to the Tape.

I would do the following things, before going to perform such Backups.

1. First Determine the estimated value of tape_size parameter and set it accordingly:

-> switch off the harware compression (via a switch on the unit or with the appropriate driver [tape_address]). To do so, read the hardware documentation

-> begin a complete backup on the tape station with compress = no

-> after the physical tape-end has been reached and the backup terminated, use the quantity output in the last BR063I message as an approximate value for the tape_size parameter.

All above steps are mentioned in this SAP Note 8707 - Explanation about init<SID>.sap parameter tape_size. Please refer it.

2. Estimate the Compression Rate which is closer to the Compression Rate provided by ur connected Tape Device Drive, by running dummy compression Run:

Use compress=only or -k only with BRBACKUP command

Please refer SAP Note 19909 - Setting compress_cmd for compress = only, to set ur compress command with option "-b 12", which is required to get much closer Compression Rate to the actual Hardware Compression rate.

e.g. compress_cmd = "compress -b 12 -c $ > $"

3. By performing the above estimation, you will come to know about the estimated Data Size which will fit in your Tape with/without H/W compression. Then perform Backup using "-k hardware" option.

Please refer these following SAP Notes to get more information.

Note 13550 - Using BRBACKUP and BRARCHIVE

Note 8707 - Explanation about init<SID>.sap parameter tape_size

Note 19909 - Setting compress_cmd for compress = only

Note 13372 - BRBACKUP reaches end of tape

Note 23234 - Backup of large databases with BRBACKUP

Regards,

Bhavik G. Shroff

[Former Member · Accepted solution]

Hi Bhavik,

Thank you so much for your detailed explanation. I will review the listed SAP Notes you had given.

Regards,

Ronald

[Former Member · Accepted solution]

Hi to All,

Thanks so much for all the help and assistance!

Regards,

Ronald