RE: Tuning RMAN backup and recovery
- From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
- To: "Limin Guo" <lguo.oracle@xxxxxxxxx>, "Oracle-L Freelists" <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 16 Nov 2007 16:01:30 -0700
I set out to specifically to test compression performance a few months
ago so I changed absolutely nothing other than adding "AS COMPRESSED
BACKUPSET" to my BACKUP DATABASE command. I'm backing up to sbt_tape
via Netbackup 6.0, but I believe the backups actually go to a disk
staging pool rather than directly to a tape drive. I've only tested
compression on this one system, so I don't have anything else to compare
it to and I'm not sure what would explain why we're seeing different
results. It seems to me that the most likely explanation is that my
bottleneck is the speed of writes to sbt_tape and those are drastically
reduced by the compression so that's where I save the time, whereas you
probably are not bottlenecked by the speed of your backup writes to disk
so you experience an increase in time due to the extra CPU overhead.
Here are my rman configurations:
RMAN> show all;
RMAN configuration parameters are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO 'SBT_TAPE';
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE SBT_TAPE TO
'%F'; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; #
default
CONFIGURE DEVICE TYPE 'SBT_TAPE' PARALLELISM 3 BACKUP TYPE TO BACKUPSET;
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' MAXOPENFILES 1 PARMS
'ENV=(NB_ORA_SCHED=User)';
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO
'/opt/oracle/product/10.2/db_1/dbs/snapcf_baandev.f'; # default
-----Original Message-----
From: Limin Guo [mailto:lguo.oracle@xxxxxxxxx]
Brandon and Robert:
Very interesting to know that it actually save time for you to use RMAN
compression than not use it.
Do you use different CONFIGURE when using compression? like channels ,
parallelization, etc.
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