Oracle Backup Compression

[Sagar_Kolhe]

Hello All,

We need to take compress onilne oracle backup. our symantec tech-suppport said that , compression is not possible for oracle through netbackup.

Kindly share your views on the same.

Thanks,

Sagar

[sdo]

A good answer to your question will depend upon how you answer this question...

Is your backup going to be saved to:

1) Basic disk? (DSU)

2) Basic disk with staging? (DSSU)

3) Advanced disk?

4) De-dupe disk?

5) VTL with dedupe?

6) VTL without de-dupe?

7) Physical tape?

8) A cloud service?

9) A mix of the above?  If so, please specify which.  And by 'a mix of the above', I mean... Will the backup reside, at any time, for any length of time (no matter how short) on any of the above backup 'landing zone' target storage types?

[Sagar_Kolhe]

physical tape . (GEN 5 Media)

[sdo · Accepted solution]

If, and only IF, the backup is going straight to LTO5 tape media, then...

1) RMAN pre-compression, before the backup data hits NetBackup, should not be a problem.

2) RMAN pre-compression could (should) be a good thing for LAN backup traffic data volumes, in that less data will be transferred, and so the backup should complete sooner - but only as long as the client (the Oracle server) is not overly stressed (by having to perform compression on the database side), and can thus sustain a decent rate of traffic (see next point).

3) Going direct to tape, should be okay - as long as the client can sustain a transfer rate higher than the minimum 'streaming rate' of the tape drive.

4) Going direct to tape with pre-compressed RMAN data will not yield any compression at the LTO5 tape head - i.e. if the Oracle client sends 2TB of data, then 2TB of tape will be used.

HTH.

[Sagar_Kolhe]

What needs to change from netbackp side. i.e oracle scripts or any other parameters. Can you please elaborate more regarding compression of oracle backup.

Thanks,

Sagar

[sdo]

RMAN compression is not a NetBackup setting.  It's an RMAN script setting.  As for the mechanics of how and what RMAN compression actually does - use Google?

If you answer this...

1) Are you wanting to use OIP?  (Oracle Intelligent Policies)

2) Or, are you wanting to use just a traditional Oracle backup policy?

...then someone should be able to give you some good pointers/advice/links.

[Sagar_Kolhe]

we are using traditonal oracle backup policy. I am asking in details because tech support said NO to compression which created doubt in my mind.

[sdo]

Weird.  Usually I have a hard time getting Oracle DBAs to disable RMAN compression (because I want to use de-dupe as a target).

Anyway - have you got to write the RMAN script yourself?  No DBA around to help you?

[Marianne]

You can search Oracle web site or even Google for rman compression examples. I found this link on Google: http://www.dba-oracle.com/t_backup_compression.htm

[Sagar_Kolhe]

DBA Team only managing the rman scripts. I am asking for my knowledge.

[Sagar_Kolhe]

If we go ahead with compression of Online oracle backup , restoration of the same data has any diferent way or it is same as normal oracle backup restoration. any recommendation or any other issues ?

[sdo]

From my limited, NetBackup only, perspective... restore/recovery should be functionally transparent, and therefore no different (in action terms) to both NetBackup and Oracle RMAN.  i.e. Oracle RMAN will decompress and restore as only it knows how... but I dare say that Oracle will have to spend an amount (unquantifiable from a NetBackup angle) of resources reconstructing data - but then we need to remember that such action can surely be considered as a core stable feature of Oracle RMAN, and so one should be justified in assuming that this should not result in any significant impact (during restore) from having used Oracle RMAN compression during the original backup.

In summary; it is out of the hands of NetBackup, both in and out, and so perhaps your question might be better put to an experienced Oracle DBA.

[emret]

You can add that line to the oracle rman sh script before the #BACKUP parameter.  with this parameter you can take the compressed oracle backup to the storage unit. 

BACKUP as compressed backupset

[Raaavan]

This is what I got from “NetBackup_AdminGuide_Oracle”  Page no .199

“Disable Oracle's compression for the duration of the database backup.

By default, Oracle disables compression. If compression is enabled, Oracle compresses unused sections in streams, and the result is unpredictable deduplication rates. If compression is enabled, run the following RMAN command from the command line to disable compression:

RMAN> CONFIGURE DEVICE TYPE SBT_TAPE BACKUP TYPE TO BACKUPSET;

If your site requires compression, you can specify compression in the NetBackup for Oracle backup policy.” 

But since destination storage unit is tape library there is no impact w.r.t. deduplication. Hence I would suggest you to test DB level compression with destination STU as LTO.

Query on recovery window –

Reference:-

http://docs.oracle.com/cd/B28359_01/backup.111/b28270/rcmcncpt.htm

From above article The “AS COMPRESSED BACKUPSET” option of the BACKUP command allows RMAN to perform binary compression of backupsets. The resulting backupsets do not need to be uncompressed during recovery (Hence it should not increase recovery window) 

Select any of the compression algorithm suit your environment i.e maximum compression (default) or CPU efficiency. This can be achieved by below command

RMAN> CONFIGURE COMPRESSION ALGORITHM TO 'alg_name'; 

Note – But make sure that hardware compression is not enabled. 

[Sagar_Kolhe]

Thanks for more information about oracle compression. (y)