Oracle Database High Availability Brandon Kuschel Jian Liu Source: Oracle Database 11g Release 2 High Availability An Oracle White Paper November 2010 http://www.oracle.com/technetwork/database/features/availability/twp-databaseha-11gr2-1-132255.pdf

Overview Human Error Protection Data Corruption Protection Oracle Flashback Technologies Oracle Recovery Manager Data Corruption Protection Fast Recovery Area Oracle Secure Backup Data Recovery Advisor Storage Failure Protection Automatic Storage Management Site Protection Oracle Data Guard Oracle GoldenGate

Oracle Database's HA Solution Set

Human Error Protection Example: Bug in SQL statement Isolation: Preventing errors via access control Faster recovery with Flashback technologies Undo: Query Undo: Versions Query: SELECT * FROM emp VERSIONS BETWEEN TIMESTAMP time1 AND time2 WHERE… Transaction Query: SELECT * FROM FLASHBACK_TRANSACTION_QUERY WHERE XID = transactionID Undo Transaction - Atomicity Full Table Undo Drop Entire Database Fine-grained access control available via Virtual Private Database feature Query: Query data at some point in time in the past. Versions Query: Retrieve all different versions of data between two points in time. Useful for seeing how and when data has changed. Transaction Query: See all changes made by a transaction. Produce SQL code to undo the transaction. Transaction: Undo a single transaction. Optionally undo dependent transactions as well. Table: Recover one or more tables to a given point in time. Drop: Restores a dropped table, including its indexes, constraints, and triggers from the dropped objects Recycle Bin. Saves the work of doing a restore then recreating all table attributes. Database: Quickly restores a database to a specific point in time by only restoring the blocks that have been changed. A normal recovery would require the entire database to be restored.

Data Corruption Protection Ex: Fault during single read/write operation Two-Phase Commit Prepare: Write to log and lock table Commit: Write to disk if ready then log as committed Prevent corruption by setting parameters Wide range of backup options RMAN (Oracle Recovery Manager) Configure backup and recovery policy Verify backups aren't corrupt Fast recovery backup Stored on disk onsite - secondary storage Only the newest files are stored here Tertiary (remote) backup Backups are copied to tape or uploaded to Amazon S3 Data Recovery Advisor Identifies the available recovery options Temporary fault can be in file system, volume, device driver, storage controller, or disk drive. Prepare phase: Each node can respond as prepared, read-only (data on node not changed by SQL statements to be committed), or abort. One abort aborts transaction. Commit phase: Send message to all nodes asking them to commit. Use DB_ULTRA_SAFE. Automatically enables checks for critical corruption: block header checks, full-block checksums, and lost-write verification Backup to disk, tape, and cloud. Provides for recovery from multiple failure situations. RMAN keeps history of all backup and recoveries and verifies all data blocks. FRA includes RMAN backups, control files, archived logs, and data file copies. Old files should have been backed up to tape before being deleted. Data recovery advisor helps save time reading through error files while preparing for recovery.

Storage Failure Protection Ex: Disk drive crash ASM (Automatic Storage Management) Database-specific RAID Block Repair Automatically: relocate valid blocks from the mirrored copy Manually: relocate specific blocks Rolling Upgrades Keeping application online while upgrading ASM ACFS and ADVM ASM Cluster File System Extends ASM functionality to support all non-Oracle database files ASM Dynamic Volume Manager Provides a general purpose volume management platform for 3rd party file system

Standby database options Site Protection Ex: fire, storm, power outage Oracle Data Guard options: Standby database up-to-date Standby database is a snapshot Use standby to perform planned maintenance in a rolling fashion Oracle GoldenGate – Distributed databases All databases are active for reading/writing Oracle Streams Standby database options Site failures - natural disasters, power outages, communications outages, etc Structure of distributed database

References Oracle Database 11g Release 2 High Availability: http://www.oracle.com/technetwork/database/features/availability/twp-databaseha-11gr2-1-132255.pdf Using Oracle Flashback Transaction Query http://docs.oracle.com/cd/B28359_01/appdev.111/b28424/adfns_flashback.htm#ADFNS01005 Oracle Recovery Manager http://www.oracle.com/technetwork/database/features/availability/rman-overview-096633.html Oracle Secure Backup http://www.oracle.com/technetwork/products/secure-backup/overview/index.html ASM in Oracle Database 10g http://www.oracle-base.com/articles/10g/automatic-storage-management-10g.php Oracle Data Guard 11g http://www.oracle.com/technetwork/database/features/availability/twp-dataguard-11gr2-1-131981.pdf Oracle GoldenGate 11g http://www.oracle.com/us/products/middleware/data-integration/goldengate11g-ds-168062.pdf?ssSourceSiteId=otnen Two-Phase Commit Mechanism http://docs.oracle.com/cd/B28359_01/server.111/b28310/ds_txns003.htm