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The SmartSync feature of Veritas Volume Manager increases the availability of mirrored volumes by only resynchronizing changed data. (The process of resynchronizing mirrored databases is also sometimes referred to as resilvering.) SmartSync reduces the time required to restore consistency, freeing more I/O bandwidth for business-critical applications. SmartSync uses an extended interface between VxVM volumes, VxFS file systems, and the Oracle database to avoid unnecessary work during mirror resynchronization and to reduce the I/O overhead of the DRL. For example, OracleŽ automatically takes advantage of SmartSync to perform database resynchronization when it is available.
Note: |
To use SmartSync with volumes that contain file systems, see the discussion of the Oracle Resilvering feature of Veritas File System (VxFS). |
The following section describes how to configure VxVM raw volumes and SmartSync. The database uses the following types of volumes:
Data volumes are the volumes used by the database (control files and tablespace files).
Redo log volumes contain redo logs of the database.
SmartSync works with these two types of volumes differently, so they must be configured as described in the following sections.
To enable the use of SmartSync with database volumes in shared disk groups, set the value of the volcvm_smartsync tunable to 1.