RMAN backup Slows down the performance of Application to dead slow
Hi ,
My application becomes dead slow when the RMAN backup is started on the database. The DBA says there is no bottelneck for the DB ,Network,CUP side. But still i have aked them to generate a awr and addm report for the period of the backup running i.e.
O Starting snapshot is the one just taken before starting the online backup.
O end snapshot is the one just taken after the end of online backup.
OS is RHEL
Following are the addm findings
Analysis Period: 15-MAR-2013 from 16:00:01 to 20:00:23
Database ID/Instance: xyz/1
Database/Instance Names: xyz
Host Name: xyz
Database Version: 10.2.0.4.0
Snapshot Range: from 10864 to 10868
Database Time: 10052 seconds
Average Database Load: .7 active sessions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
FINDING 1: 100% impact (10052 seconds)
--------------------------------------
The SGA was inadequately sized, causing additional I/O or hard parses.
RECOMMENDATION 1: DB Configuration, 100% benefit (10052 seconds)
ACTION: Increase the size of the SGA by setting the parameter
"sga_target" to 1050 M.
ADDITIONAL INFORMATION:
The value of parameter "sga_target" was "600 M" during the analysis
period.
SYMPTOMS THAT LED TO THE FINDING:
SYMPTOM: Wait class "User I/O" was consuming significant database time.
(36% impact [3630 seconds])
SYMPTOM: Hard parsing of SQL statements was consuming significant
database time. (2.1% impact [206 seconds])
So my questiion is, should i increase the sga size what is going to be the impact or how to decide the exact sga size needed as this is a DSS system database so lot many procedure are run in the night for loading data and calculation.
Or how can RMAN slow donw the application when there is less sga avalible.
Also i want to know standard size of sga for DSS system. This DB is of 1TB size and have long running procedure batch jobs of about 4 hrs.
Please need a quick reply
Regards
Waiting for your all responce.