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Data Guard Load Balancing Tips
Donald K. Burleson |
Oracle Data Guard Load Balancing
Standby databases can contribute towards load
balancing on the primary database. The ad-hoc reporting and backup
operation activities can be off loaded to the standby database,
reducing load on the primary database.
The
physical Oracle instance
can be opened in read-only mode and will
cater to the DBA’s reporting requirements. Careful consideration is
required when selecting the operating mode because as long as a
physical Oracle instance
is open in read-only mode, it cannot be
synchronized with the primary database.
Load Balancing
As a result, the most up-to-date data will not
be available for reporting. If the reporting requirements of the
organization demand the most up-to-date information from the primary
database or real-time data, a logical Oracle instance
will be the
obvious choice. A logical Oracle instance
is always open in
read-only or read/write mode and can keep the data in sync with the
primary database while providing reporting services.
If the backup and recovery strategy includes a
traditional online or offline backup of the database along with Data
Guard configuration, the backup operation can be offloaded from the
primary database to the standby database.
Automated Management of Data Guard Load Balancing
The managed recovery mode of the standby
database in Oracle8i greatly reduced the amount of time a DBA needed
to spend on managing this configuration. In managed recovery mode,
the archived redo logs are automatically transferred from the
primary database to the Oracle instance
and applied to the standby
database.
The only time a DBA needs to monitor and
maintain the Oracle instance
is if there are gaps in the archived
redo logs on the standby site. Details about gap sequence and its
resolution are provided in Chapter 2, “Data Guard Architecture.”
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