New Backup & Recovery Features in Enterprise Manager 10g

 

Timothy Chien, System Technologies, Oracle Corporation

Enterprise Manager 10g is Oracle’s single, integrated solution for administering and monitoring applications and systems that are based on the Oracle technology stack. Enterprise Manager (EM) offers a number of features to assist DBAs with the management of database backup and recovery, an essential component of an overall high availability strategy. These features include management of backup set/image copies, a pre-configured backup strategy, point-in-time recovery, and new flashback capabilities. This tech tip outlines key enhancements in Enterprise Manager 10g for backup and recovery management.

Backup Management

The new Manage Current Backups page lists all backups, both backup sets and image copies, as recorded in the Recovery Manager repository. Each backup is shown, with its tag, completion time, backup device type, and the type of content (e.g. archived log, data file) contained in each backup set. By drilling down into content type or pieces, each physical file size, or compressed size if applicable, is displayed. Backup sets can be filtered for viewing according to status, content type, and completion time.

Figure 1: Manage Current Backups Page

Several tasks are simplified from this page:

• One-step procedure to re-catalog recovery files, keeping the catalog up to date when new files are added to the flash recovery area or backup set directory is moved
• Fast crosscheck validation to ensure that backup information in the recovery catalog or control file is synchronized with actual files on disk or the media management catalog
• When the physical backups on disk or tape are taken offline or when certain backups are to be excluded from recovery procedures, the associated backup records in the RMAN repository can be easily switched to UNAVAILABLE status. RMAN will skip over UNAVAILABLE backups when recovery is performed.
• Remove backups from media and associated backup records from RMAN repository which no longer satisfy the specified retention policy (i.e. "obsolete")
• Remove backup records from the RMAN repository for backups which have been physically removed from disk or tape (i.e. "expired")

Oracle-Suggested Backup Strategy

EM introduces a pre-configured RMAN backup configuration, the "Oracle-Suggested" Backup Strategy that provides performant and efficient recoverability to any point within the last 24 hours by employing the Oracle Database 10g RMAN Flash Recovery Area, Incrementally Updated Backups, and Block Change Tracking.  Click here for more information on Oracle Database 10g RMAN features.

Figure 2: Oracle-Suggested Strategy Selection Page

In this strategy, a full database backup is taken on the first day, followed by an incremental backup on day two. Archived redo logs can be used to recover the database to any point in either day. For day three and onwards, the previous day's incremental backup is merged with the data file copy and a current incremental backup is taken, allowing fast recovery to the beginning of the current day, and redo logs can be used to recover the database to any point during the current day.

Additional EM Features

• Flexible and customizable backup configurations
• Step-by-step wizard to recover at the block, table, tablespace, datafile, or database level,
• Wizard driven tablespace-point-in-time-recovery (TSPITR), as shown below:

Figure 3: Perform Recovery Wizard

• Test backup and restore to validate backup configurations
• Enable controlfile and SPFILE autobackup, block change tracking, and configure flash recovery area parameters, including retention policy, as shown below:

Figure 4: Configure Backup Settings: Policy

 

Flashback Database & Table

Oracle Database 10g provides new capabilities for 'rewinding' databases and tables to a previous point-in-time quickly and easily. Flashback Database provides database point in time recovery without the need to restore a database backup. Flashback Table restores the tables while automatically maintaining its associated attributes such as current indexes, triggers, and constraints; it does not require the DBA to find and restore application specific properties. In addition, accidental table drops can also be 'un-done' using Flashback Drop.  Click here for more information on the new Flashback Technology.

EM provides intuitive wizards to accomplish all flashback operations. For example, to prepare for Flashback Table, the wizard allows the DBA to locate the appropriate tables and row versions that exist within a specified time interval, as shown below:

Figure 5: Perform Recovery: Flashback Table

Figure 6: Perform Recovery: Flashback Versions Query Filter

 

Summary

 

With the rich backup and recovery management features in Enterprise Manager 10g, DBAs can get up and running with:

 

• On-demand and scheduled backups, including a pre-configured 24 hour recovery window strategy
• Flexible point-in-time restore and recovery at the database, datafile, archived logs, tablespaces, or table level
• Single view of all backups and their attributes, with one-step re-cataloging, crosscheck, and deletion of obsolete/expired backups
• Reliable notification of backup job completion status via EM alerts framework
• Easy modification of common backup and recovery configuration settings
• New flashback technologies to quickly "rewind" database and tables back in time

 

References

 

2-Day DBA Training (Ch. 9 "Performing Backup & Recovery")

RMAN on OTN

 

Tim Chien (Timothy.Chien@Oracle.com) is a product manager with Oracle's High Availability and Storage Management Group. His extensive product management and product marketing experience includes server systems, AS, and database products.