Lesson 1
Oracle Backup Strategies
A backup strategy is only as effective as the utilities available to the user. The folowing table compares the backup utilities and features of legacy Oracle with those of Oracle8.
Backup Utilities in Oracle
This table compares the new backup utilities and features of Oracle9i with those of Oracle8.
| Utility/Main Features | Sub-Feature | Oracle8 | Oracle8i |
| RMAN | Interactively create and run scripts | Did not support Wizards | Supports wizards for creating and executing scripts |
| Fast-Start Fault Recovery | Had a similar feature “Transparent Application Failover,” but worked only on Oracle Parallel Server | Feature introduced within Oracle8i | |
| Fast-Start Fault Recovery | Fast-Checkpointing | Not supported | This feature reduces the number of data buffers/blocks that are read during recovery. |
| Fast-Start Fault Recovery | On-Demand Rollback | Not supported | This feature allows recovering only those records from dead transactions, which are required by a transaction. This helps in faster recovery. |
| Parallel Rollback | Not supported | This feature performs rollback of data in parallel. | |
| Supported standby database, but the archived redo logs had to be copied and applied manually from the primary production database to the standby database. | The standby database is automated, so the archived redo log files are moved to the standby database and applied by Oracle8i database. | ||
| Automated Standby Database | |||
| Read-Only Database | Not supported, the standby database was not open to the users. | This feature allows the users to access a standby database in a read-only manner. This helps in reducing the load of long queries and reports from the production database to a standby read-only{{{fix to avoid break}}}database. | |
| Export/Import utility | Query criteria for export | Not supported | This feature allows the specification of criteria for selecting records for a table to be unloaded by Export. |
| Export/Import utility | Multiple dump files and dump tapes | Not supported | This feature allows the user to specify multiple larger dump files and dump tapes to export the database. This allows users to circumvent the previous 2GB limit for export dump files. |
| Export/Import utility | LOB and objects | Not supported | This feature allows the user to export and import LOB data and objects. |
| Repairing database | DBMS_REPAIR | Not supported | Oracle8i includes a package, DBMS_REPAIR, which helps detect and repair block corruption on tables, indexes, and other objects. |
| Reading redo logs | LogMiner | Not supported | LogMiner, a feature, is a fully relational tool which allows redo log files to be read, analyzed, and interpreted by the user using SQL. This is helpful, because the log files contain all of the data needed to perform database recovery. |
| Oracle Enterprise Manager (OEM) | Supported | Some features have been added to it | |
| Oracle Enterprise Manager (OEM) | Availability on all platforms | Supported only on MS Windows NT | Version 2.0 is Java based, hence it is available on all platforms. |
Oracle Recovery Features
The Recovery features within Oracle allow you to:
These are some of the most useful features, which we will learn in greater detail, within this module.
This module discusses:
- Save the archive redo log files within up to five locations. This can be set using a parameter within the init.ora file. Engage multiple archival processes during the instance startup, providing better performance for instance recovery.
- Significantly increase the performance of the standby database. Within Oracle, the archive log files can be automatically sent across to the remote standby database, where they are automatically verified and applied to the database.
- Create a read-only database. This feature is useful in a standby database as this database can be used for executing large queries and reports, without affecting the performance of the production database.
- More efficiently suspend the database for backup purposes.
- Increase the performance of check pointing and recovery of dead and parallel transactions, using Fast-Start Fault Recovery, another new feature.
These are some of the most useful features, which we will learn in greater detail, within this module.
This module discusses:
- How to describe the concept and process of Fast-Start Fault Recovery
- Explain the steps involved in Fast-Start rollback
- Describe the effects of Fast-Start checkpointing
- Implement Fast-Start parallel rollback
- Explore the features of a read-only database
- Create a standby database