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Oracle deduplication rate is very slow

Germano
Level 3
Partner Accredited

Hello guys,

My name is Germano, andI work for Consulting Veritas in Brazil. (luis.germano@veritas.com).

I have deduplication performance problem in backup of an Oracle 12c database, on NetBackup 8.1.1 (about 18%)

I am using a 5240 Appliance as a Media Server with 2 10Gbps interface in LACP.

The database has a 9TB and does not have modifications.

I've disabled encryption, compression, and backup optimization in RMAN, but I still can not improve the rates.

Here are the RMAN deafults settings and the backup script I'm using:

RMAN> SHOW ALL;

RMAN configuration parameters for database with db_unique_name CDBXML0 are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 3;
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO 'SBT_TAPE';
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE 'SBT_TAPE' TO '% F';
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '% F'; # default
CONFIGURE DEVICE TYPE SBT_TAPE PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE SBT_TAPE TO 1; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE SBT_TAPE TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE CHANNEL DEVICE TYPE 'SBT_TAPE' PARMS 'SBT_LIBRARY = / usr / openv / netbackup / bin / libobk.so64, ENV = (NB_ORA_POLICY = ORACLEDB02_CDBXML_FULL, NB_ORA_SERV = appnbumaster01.intra.goias.gov.br)';
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE; # default
CONFIGURE RMAN OUTPUT TO KEEP FOR 7 DAYS; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '+ FRA / snap_controlfile_cdbxml0.f';

Script:

RMAN_SBT_LIBRARY="/usr/openv/netbackup/bin/libobk.so64"
RMAN_ORA_POLICY="ORACLEDB02_CDBXML_FULL"
RMAN_ORA_SERV="appnbumaster01.intra.goias.gov.br"

run
{
allocate channel t1 DEVICE TYPE 'SBT_TAPE'
PARMS "SBT_LIBRARY=${RMAN_SBT_LIBRARY},ENV=(NB_ORA_POLICY=${RMAN_ORA_POLICY},NB_ORA_SERV=${RMAN_ORA_SERV})";
allocate channel t2 DEVICE TYPE 'SBT_TAPE'
PARMS "SBT_LIBRARY=${RMAN_SBT_LIBRARY},ENV=(NB_ORA_POLICY=${RMAN_ORA_POLICY},NB_ORA_SERV=${RMAN_ORA_SERV})";
allocate channel t3 DEVICE TYPE 'SBT_TAPE'
PARMS "SBT_LIBRARY=${RMAN_SBT_LIBRARY},ENV=(NB_ORA_POLICY=${RMAN_ORA_POLICY},NB_ORA_SERV=${RMAN_ORA_SERV})";
allocate channel t4 DEVICE TYPE 'SBT_TAPE'
PARMS "SBT_LIBRARY=${RMAN_SBT_LIBRARY},ENV=(NB_ORA_POLICY=${RMAN_ORA_POLICY},NB_ORA_SERV=${RMAN_ORA_SERV})";
allocate channel t5 DEVICE TYPE 'SBT_TAPE'
PARMS "SBT_LIBRARY=${RMAN_SBT_LIBRARY},ENV=(NB_ORA_POLICY=${RMAN_ORA_POLICY},NB_ORA_SERV=${RMAN_ORA_SERV})";
allocate channel t6 DEVICE TYPE 'SBT_TAPE'
PARMS "SBT_LIBRARY=${RMAN_SBT_LIBRARY},ENV=(NB_ORA_POLICY=${RMAN_ORA_POLICY},NB_ORA_SERV=${RMAN_ORA_SERV})";
 
BACKUP
FILEPERSET 1
INCREMENTAL LEVEL 0
TAG 'FULLBACKUPSET_L0'
FORMAT '${NOME_BACKUP}_%d_S_%s_P_%p_T_%t'
DATABASE;

release channel t1;
release channel t2;
release channel t3;
release channel t4;
release channel t5;
release channel t6;
}

Any ideas?

Thanks!

3 REPLIES 3

Nicolai
Moderator
Moderator
Partner    VIP   

Did you see :

Veritas NetBackup™ for Oracle Administrator's Guide - Deduplication best practices

https://www.veritas.com/content/support/en_US/doc/16226115-126559565-0/v51065533-126559565

Any row compression in the Oracle database / or is the database so active that the contens of the database is completly changed - like a datawarehouse ?

In general don't expect to big dedupe savings on Oracle databases.

Marianne
Moderator
Moderator
Partner    VIP    Accredited Certified

@Germano

Maybe my understanding is incorrect, but it seems over here if encryption is turned off and then turned on again:

CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default

And over here compression turned on?

CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE; # default

If my understanding is correct, then this is the reason for poor dedupe rates.
Encryption and compression should be turned off. 

Tousif
Level 6

Hello,

 

Is that issue with performance or dedup ratio?

If it is related to  dedup ratio:

To simplify the troubleshooting, I would recommend to go with the legacy method and standard Oracle (NBU) script and test the backup to isolate the issue. We have to identify what is causing a problem (Client or MSDP).

 

Regards,