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Best Practices for Oracle 11g Backup and Recovery using RMAN and Dell EqualLogic Snapshots
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7 Conclusions from test results
This section describes key observations captured during each test. The database backup and recovery
operations were performed using RMAN full backup, RMAN incremental backup and EqualLogic
snapshots. We also studied the point-in-time recovery operations of the database using Oracle’s
FLASHBACK DATABASE feature and EqualLogic snapshots.
7.1 Database backup – key observations
CPU Utilization
• We measured a significant impact on CPU utilization on the database server while performing
RMAN backup operations. The CPU utilization increased significantly during the backup
process. Also, database performance as measured by transactions per second (TPS) and
Average response time was significantly impacted for a brief period (~two minutes) at the
beginning of RMAN backup processing.
• Increasing the frequency of RMAN incremental backups amplifies the processing performance
penalty described above.
• By using EqualLogic snapshots in the user managed backup scenario we were able to offload
the RMAN CPU performance penalty to a dedicated backup server. In this scenario the impact
on database performance was limited to a brief reduction in TPS and increase in response time
while the database was placed in hot backup mode. During the rest of the backup operation
the production database server was not affected.
Time to create backup
The time to create backups using three different methods is shown in Figure 10. The RMAN
incremental backup time represents the total time required to create a level 0 backup (56 minutes)
plus a level 1 backup (50 minutes).