Which two are true about the usage of DBMS_ROLLING? (Choose two.)
E: The trailing group contains the original primary database and standby databases that will protect the original primary during the rolling upgrade process.
D: Databases in the leading group are upgraded first; hence the name leading group. The leading group contains the designated future primary database, and the physical standbys that you can configure to protect the designated future primary. The future primary is first converted into a logical standby database and then the new database software is installed on it and the upgrade process is run. Other standby databases in the leading group also must have their software upgraded at this point.
Note: To upgrade the database software in an Oracle Data Guard configuration in a rolling fashion, you first designate a physical standby as the future primary database.
Conceptually, the rolling upgrade process splits the Oracle Data Guard configuration into two groups: the leading group (LG) and the trailing group (TG).
In which two cases is it possible to change the protection mode to maximum protection using Enterprise Manager Cloud Control? (Choose two.)
Maximum protection mode requires the SYNC redo transport mode to be set on at least one standby database.
Note:
The Maximum protection mode ensures that no data loss will occur if the primary database fails. To provide this level of protection, the redo data needed to recover a transaction must be written to both the online redo log and to the standby redo log on at least one synchronized standby database before the transaction commits. To ensure that data loss cannot occur, the primary database will shut down, rather than continue processing transactions, if it cannot write its redo stream to at least one synchronized standby database.
References:
http://www.oracle.com/technetwork/oem/framework-infra/wp-em12c-building-ha-level3-1631423.pdf
You must configure an Oracle Data Guard environment consisting of:
1. A primary database
2. One Physical Standby Database
3. One Logical Standby Database
You must meet these requirements:
1. Primary database availability should not be compromised by the availability of the standby databases.
2. Under normal operations, transactions executed on the primary database should not commit before redo is written to disk on both the primary database and at least one standby database.
Which redo transport mode and which protection mode would you configure to meet these requirements?
The Maximum Availability protection mode provides the highest level of data protection that is possible without compromising the availability of a primary database. Transactions do not commit until all redo data needed to recover those transactions has been written to the online redo log and to at least one synchronized standby database. If the primary database cannot write its redo stream to at least one synchronized standby database, it operates as if it were in maximum performance mode to preserve primary database availability until it is again able to write its redo stream to a synchronized standby database.
This mode ensures that no data loss will occur if the primary database fails, but only if a second fault does not prevent a complete set of redo data from being sent from the primary database to at least one standby database.
When a transport is performed using SYNC/AFFIRM, the primary performs write operations and waits for acknowledgment that the redo has been transmitted synchronously to the physical standby and written to disk. A SYNC/AFFIRM transport provides an additional protection benefit at the expense of a performance impact caused by the time required to complete the I/O to the standby redo log.
You must design an Oracle Data Guard configuration for an OLTP database that meets these permanent requirements:
1. Data loss is not permitted.
2. Read-only applications should not connect to the primary database instance.
Additionally, there are these requirements, only one of which is ever done at any one time:
1. It should be possible to apply designated patches with a minimum amount of downtime.
2. Upgrading to a new database release should be performed with the least possible amount of downtime.
3. New application software releases should be tested against an exact and up-to-date replica of the primary database.
Which configuration meets these requirements with the fewest databases?
Which three statements are true about snapshot standby databases? (Choose three.)
C: Flashback Database is similar to conventional point-in-time recovery in its effects. It enables you to return a database to its state at a time in the recent past. Flashback Database uses its own logging mechanism, creating flashback logs and storing them in the fast recovery area. You can only use Flashback Database if flashback logs are available. Flashback Database is used to convert a snapshot standby database back into a physical standby database.
E: When we convert the physical standby database to snapshot standby database a guaranteed restore point is created. This guaranteed restore point is used to flashback a snapshot standby database to its original state.
