Relation between RMAN retention period and control_file_record_keep_time (Doc ID 397269.1)

Relation between RMAN retention period and control_file_record_keep_time 

PURPOSE

Guideline to set CONTROL_FILE_RECORD_KEEP_TIME in relation to the RETENTION POLICY

SCOPE


RMAN backup keeps the backup metadata information in the reusable section of the controlfile. It depends on the parameter CONTROL_FILE_RECORD_KEEP_TIME. CONTROL_FILE_RECORD_KEEP_TIME specifies the minimum number of days before a reusable record in the control file can be reused. In the event a new record needs to be added to a reusable section and there is not enough space then it will delete the oldest record, which are aged enough.

Backup retention policy is the rule to set regarding which backups must be retained (whether on disk or other backup media) to meet the recovery and other requirements.

If the CONTROL_FILE_RECORD_KEEP_TIME is less than the retention policy then it may overwrite the RMAN metadata in the reusable records prior to obsoleting them. Without the metadata RMAN cannot delete the backups. Therefor it is recommended that the CONTROL_FILE_RECORD_KEEP_TIME should be set to value higher than the retention policy configuration.

Please note the default control_file_record_keep_time is 7 days.


NOTE: Best practice is to NOT set to a value greater than 10. If you need retention greater than this in the controlfile, you should use an RMAN catalog .

Bigger values, will hold data for more time, But will also have bigger the size of the controlfile, which in turn can cause performance issue are more entries from controlfile need to be read.

The exception is when using Database in the Oracle Cloud, control_file_record_keep_time default value after enable backup is 40 without using Recovery Catalog

Typically control_file_record_keep_time is by default set to higher value in cloud DB systems which is approved by database cloud engineering group.

Formula

CONTROL_FILE_RECORD_KEEP_TIME = retention period + level 0 backup interval + 1

For e.g.

e.q. level 0 backup once a week with retention policy of a recovery windows of 14 days then in this case the CONTROL_FILE_RECORD_KEEP_TIME should be 14+7+1=22

To be on safer side you can always add + 2 or 3 days to above formula.

Ideally its recommended to configure a recovery catalog so that information about the backups are present in recovery catalog even though the controlfile section gets reused based on the control_file_record_keep_time due to space pressure.

RMAN-07553 / RMAN-07554 - POST DATABASE UPGRADE TO 19C (Doc ID 2887420.1)

 RMAN-07553 / RMAN-07554 - POST DATABASE UPGRADE TO 19C

APPLIES TO:Oracle Database - Enterprise Edition - Version 19.7.0.0.0 and later
Information in this document applies to any platform.

SYMPTOMS

getting warning message while executing delete obsolete


rman target /



RMAN> CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF X DAYS;

RMAN> DELETE OBSOLETE;

RMAN retention policy will be applied to the command

RMAN retention policy is set to recovery window of X days

RMAN-07554: warning: CONTROL_FILE_RECORD_KEEP_TIME is too large (n days)

or

RMAN-07553: warning: RECOVERY WINDOW is more than CONTROL_FILE_RECORD_KEEP_TIME

In the above example, the parameter control_file_record_keep_time is set to n days which is greater than 30 (RMAN-07554) or recovery window is greater than CONTROL_FILE_RECORD_KEEP_TIME(RMAN-07553)
CHANGES

RMAN-07554 - Recovery catalog is not used and CONTROL_FILE_RECORD_KEEP_TIME is set to greater than 31

RMAN-07553 - Recovery catalog is not used and recovery window is greater than CONTROL_FILE_RECORD_KEEP_TIME

CAUSE


These warning messages are printed intentionally during report obsolete / delete obsolete commands which is expected to warn user if recovery window is > 31 days in nocatalog mode. Also, it warns
if control_file_record_keep_time is < recovery window in nocatalog mode.

SOLUTION

These warning messages are introduced to suggest user to use catalog db if control_file_record_keep is greater than 31 or control_file_record_keep_time is < recovery window. To avoid these warning messages, use recovery catalog or set the value for CONTROL_FILE_RECORD_KEEP_TIME to less than 31 for RMAN-07554 and set the value of control_file_record_keep_time greater than recovery window when recovery catalog is not used.

ORACLE EXADATA ARCHITECTURE

ORACLE EXADATA ARCHITECTURE  

Oracle Exadata's architecture is a sophisticated blend of hardware and software designed to optimize the performance, scalability, and reliability of Oracle databases. It's a specialized platform for running Oracle Database, and it's engineered to deliver high performance for both OLTP (Online Transaction Processing) and OLAP (Online Analytical Processing) workloads.

Key Components of Oracle Exadata Architecture

1. Database Servers

   • Function: Host Oracle Database instances.
   • Features: Optimized for database processing with high-performance CPUs and large memory capacity.

2. Storage Servers

   • Function: Provide storage for the Exadata platform.
   • Types: Include both High Performance (Flash storage) and High Capacity (Hard Disk Drive) storage servers.
   • Features: Equipped with Exadata software for intelligent data caching, compression, and query offloading.

3. Exadata Software

   • Smart Scan: Reduces data transfer between storage and database servers by performing query processing close to the data.
   • Hybrid Columnar Compression: Highly efficient data compression technique to reduce storage footprint and improve performance.
   • Flash Cache: Automatically caches frequently accessed data in flash storage for faster access.
   • Storage Indexes: Minimize disk I/O by keeping track of data ranges stored in each disk.

4. InfiniBand Network

   • Function: Connects database and storage servers.
   • Features: Provides high bandwidth and low latency communication between servers.

5. Oracle Real Application Clusters (RAC)

   • Function: Allows multiple database servers to access a single database.
   • Benefit: Provides high availability and scalability for databases.

6. Automated Storage Management (ASM)

   • Function: Manages disk storage for Oracle Database files.
   • Benefit: Optimizes storage performance and provides redundancy.

Architecture Design Principles

1. High Performance

   • Engineered to maximize database performance.
   • Minimizes disk I/O through intelligent data storage and retrieval.

2. Scalability

   • Scales out by adding more database and storage servers.
   • Supports growth in data volume and user load.

3. High Availability

   • Redundant hardware and software components to minimize downtime.
   • Oracle RAC for database high availability.

4. Security

   • Advanced security features at both the database and storage levels.
   • Includes encryption, data redaction, and access controls.

5. Consolidation

   • Suitable for consolidating multiple databases onto a single platform.
   • Supports mixed workloads effectively.

Advanced Components of Oracle Exadata Architecture

1. Smart Flash Cache

   • Description: A key feature of Exadata, it's essentially a second level of cache using flash memory.
   • Function: Improves performance by storing frequently accessed data in flash memory, reducing the need to access data from slower hard disk drives.

2. ExaFusion

   • Purpose: Optimizes the Oracle Database for Exadata hardware, especially for OLTP workloads.
   • Benefit: Drastically reduces the latency for database operations, improving overall transaction performance.

3. I/O Resource Management (IORM)

   • Function: Manages I/O bandwidth on storage servers.
   • Use Case: Ensures critical databases and applications receive priority access to storage resources, especially useful in consolidated environments.

4. Elastic Configurations

   • Flexibility: Allows customization of Exadata configurations to match specific workload requirements.
   • Scalability: Supports adding or removing resources (CPU, memory, storage) as needed.

5. Exadata Storage Expansion Racks

   • Purpose: Provides additional storage capacity for Exadata environments.
   • Integration: Seamlessly integrates with existing Exadata Database Machines to expand storage without sacrificing performance.

Software Enhancements

1. Exadata Storage Server Software

   • Key Features: Includes Smart Scans, Storage Indexes, and Hybrid Columnar Compression.
   • Advantage: Optimizes data storage and retrieval processes, greatly enhancing query performance and reducing storage costs.

2. Database In-Memory on Exadata

   • Function: Accelerates analytics by storing data in a columnar format in memory.
   • Benefit: Significantly speeds up OLAP queries, making Exadata ideal for mixed workload environments.

3. Exadata System Software

   • Updates: Regularly updated to introduce new features, enhancements, and performance improvements.
   • Customization: Allows for fine-tuning of Exadata's performance characteristics to suit specific application needs.

Network Enhancements

1. High-Speed InfiniBand Networking

   • Feature: Dual-redundant InfiniBand network fabric that connects all components.
   • Performance: Offers extremely high bandwidth and low latency communication, essential for distributed database systems like RAC.

2. Ethernet Network Connectivity

   • Function: Provides connectivity to the broader data center network.
   • Integration: Facilitates communication between Exadata and other systems, including potential cloud-based resources.

System Management and Monitoring

1. Oracle Enterprise Manager

   • Tool: Comprehensive management suite for Exadata.
   • Capabilities: Includes performance monitoring, configuration management, and automated patching.

2. Automated Diagnostics and Repair

   • Feature: Exadata's software can automatically diagnose hardware and software issues.
   • Response: In many cases, it can initiate corrective actions without human intervention.

Conclusion

The Oracle Exadata architecture represents a highly integrated, sophisticated environment designed specifically for high-performance Oracle databases. Its blend of advanced hardware, specialized software, and network technologies makes it uniquely capable of handling a wide range of demanding database workloads. From high-volume transaction processing to complex analytical queries, Exadata's architecture is engineered to deliver unparalleled performance, scalability, and reliability.