11g Data Guard New Features
Real-Time Query: In Oracle Database 8i it was possible to bring a standby database into READ ONLY mode so that it could be used for reporting purposes, but it was necessary to switch it back to standby mode for reapplication of pending change vectors from the archived redo logs transported from the primary database. Oracle Database 11g now lets me run queries in real time against any physical standby database without any disturbance to receipt and application of redo.
Snapshot Standby Databases: Oracle Database 11g offers another intriguing prospect: the ability to open a physicalstandby database for testing or QA purposes while simultaneously collecting production changes for immediate reapplication in case disaster recovery is required. This snapshot standbydatabase still accepts redo information from its primary, but unlike the first two standby types, it does not apply the redo to the database immediately; instead, the redo is only applied when the snapshot standby database is reconverted back into a physical standby. This offers significant leverage because in theory, a QA environment that requires specifically dedicated, identical hardware is no longer required.
Improved Handling of Role Transitions: The addition of standby snapshot databases brings the total of different Data Guard standby database types to three (physical, logical, and snapshot), so Oracle Database 11g also makes it much easier to transition between these different roles via either Data Guard Broker (DGB) command line execution or Enterprise Manager Grid Control. Role transitions are simpler to execute and complete more quickly than in earlier releases.
Improvements to Rolling Database Upgrades: Oracle Database 11g supports rolling database upgrades to be performed against a physical standby database by first transforming it into a logical standby database with a few simple commands before the upgrade begins. Once the upgrade is done, the logical standby database is reverted to its original physical standby state. Oracle 11gleverages this capability as well as the improved speed and simplicity of role transitions to perform system and database patching in a fraction of the time it would’ve taken in earlier releases, and it’s especially powerful in a Real Application Clusters (RAC) database environment.
SQL Apply Enhancements: Logical standby databases are obviously central to these new role transition features, but they use SQL Apply technology to apply change vectors to data. It therefore makes sense that Oracle Database 11g provides significant improvements to this crucial part of Data Guard architecture. SQL Apply now supports parallel DDL execution, Fine-Grained Auditing (FGA), Virtual Private Database (VPD), and Transparent Data Encryption (TDE), as well as simpler real-time SQL Apply reconfiguration and tuning.
Enhanced Redo Logs Transport: Physical standby databases have always used archived redo logs for application of change vectors to data. Oracle Database 11g augments redo transport with some long-overdue features, including compressionand SSL authentication of redo logs while they’re being transmitted between the primary and standby sites.
Heterogeneous DataGuard: Oracle Database 11g allows the primary and standby databases to use different operating systems (for example, Windows 2003 Server and Oracle Enterprise Linux) as long as both operating systems support the same endianness.
Fast Start Failover Improvements: Oracle introduced this feature set in Release 10gR2, but it’s been enhanced significantly in Oracle 11g to permit much finer-grained control over the conditions under which a fast-start failover would be initiated.
“Live Cloning” of Standby Databases: Finally, Oracle 11g has made it extremely simple to set up a standby database environment because Recovery Manager(RMAN) now supports the ability to clone the existing primary database directly to the intended standby database site over the network via the DUPLICATE DATABASE command set while the target database is active. This means it’s no longer necessary to first generate, then transmit, and finally restore and recover RMAN backups of the primary database on the standby site via tedious (and possibly error-prone!) manual methods; instead, RMAN automatically generates a conversion script in memory on the primary site and uses that script to manage the cloning operation on the standby site with virtually no DBA intervention required.
Real-Time Query: In Oracle Database 8i it was possible to bring a standby database into READ ONLY mode so that it could be used for reporting purposes, but it was necessary to switch it back to standby mode for reapplication of pending change vectors from the archived redo logs transported from the primary database. Oracle Database 11g now lets me run queries in real time against any physical standby database without any disturbance to receipt and application of redo.
Snapshot Standby Databases: Oracle Database 11g offers another intriguing prospect: the ability to open a physicalstandby database for testing or QA purposes while simultaneously collecting production changes for immediate reapplication in case disaster recovery is required. This snapshot standbydatabase still accepts redo information from its primary, but unlike the first two standby types, it does not apply the redo to the database immediately; instead, the redo is only applied when the snapshot standby database is reconverted back into a physical standby. This offers significant leverage because in theory, a QA environment that requires specifically dedicated, identical hardware is no longer required.
Improved Handling of Role Transitions: The addition of standby snapshot databases brings the total of different Data Guard standby database types to three (physical, logical, and snapshot), so Oracle Database 11g also makes it much easier to transition between these different roles via either Data Guard Broker (DGB) command line execution or Enterprise Manager Grid Control. Role transitions are simpler to execute and complete more quickly than in earlier releases.
Improvements to Rolling Database Upgrades: Oracle Database 11g supports rolling database upgrades to be performed against a physical standby database by first transforming it into a logical standby database with a few simple commands before the upgrade begins. Once the upgrade is done, the logical standby database is reverted to its original physical standby state. Oracle 11gleverages this capability as well as the improved speed and simplicity of role transitions to perform system and database patching in a fraction of the time it would’ve taken in earlier releases, and it’s especially powerful in a Real Application Clusters (RAC) database environment.
SQL Apply Enhancements: Logical standby databases are obviously central to these new role transition features, but they use SQL Apply technology to apply change vectors to data. It therefore makes sense that Oracle Database 11g provides significant improvements to this crucial part of Data Guard architecture. SQL Apply now supports parallel DDL execution, Fine-Grained Auditing (FGA), Virtual Private Database (VPD), and Transparent Data Encryption (TDE), as well as simpler real-time SQL Apply reconfiguration and tuning.
Enhanced Redo Logs Transport: Physical standby databases have always used archived redo logs for application of change vectors to data. Oracle Database 11g augments redo transport with some long-overdue features, including compressionand SSL authentication of redo logs while they’re being transmitted between the primary and standby sites.
Heterogeneous DataGuard: Oracle Database 11g allows the primary and standby databases to use different operating systems (for example, Windows 2003 Server and Oracle Enterprise Linux) as long as both operating systems support the same endianness.
Fast Start Failover Improvements: Oracle introduced this feature set in Release 10gR2, but it’s been enhanced significantly in Oracle 11g to permit much finer-grained control over the conditions under which a fast-start failover would be initiated.
“Live Cloning” of Standby Databases: Finally, Oracle 11g has made it extremely simple to set up a standby database environment because Recovery Manager(RMAN) now supports the ability to clone the existing primary database directly to the intended standby database site over the network via the DUPLICATE DATABASE command set while the target database is active. This means it’s no longer necessary to first generate, then transmit, and finally restore and recover RMAN backups of the primary database on the standby site via tedious (and possibly error-prone!) manual methods; instead, RMAN automatically generates a conversion script in memory on the primary site and uses that script to manage the cloning operation on the standby site with virtually no DBA intervention required.