Oracle database smart flash cache
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The document discusses Oracle Database Smart Flash Cache, a feature that allows users to expand the effective size of the database buffer cache using flash memory, improving performance by reducing I/O calls to storage. It outlines the flash cache lifecycle for reading, writing, and evicting data, as well as advantages such as lower loads on shared storage. The implementation notes that smart flash cache works with specific operating systems (Oracle Linux and Solaris) and provides guidelines for setting up flash cache hardware and database parameters.
Oracle database smart flash cache
- 1. Oracle database Smart Flash Cache Johan Louwers Johan.Louwers@capgemini.com
- 2. Oracle Database – Smart Flash Cache Database Smart Flash Cache. This feature is available on Solaris and Oracle Enterprise Linux and allows customers to increase the effective size of the Oracle database buffer cache without adding more main memory to the system. For transaction-based workloads, Oracle database blocks are normally loaded into a dedicated shared memory area in main memory called the System Global Area (SGA). Database Smart Flash Cache allows the database buffer cache to be expanded beyond the SGA in main memory to a second level cache on flash memory. Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 2
- 3. Oracle Database – SGA Memory Architecture SGA (System Global Area) • Java Pool • Shared Pool • Redo Buffer • Large Pool • Streams Pool • Buffer Cache Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 3
- 4. Oracle Database – Flash Cache Lifecycle A) Storage read • When a block is retrieved from the storage it is stored within the buffer cache of the system global area. • When the block is deemed no longer needed it is, traditionally, removed from the buffer cache and a new call to the storage is done when it is needed again. Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 4
- 5. Oracle Database – Flash Cache Lifecycle A) Storage read • When a block is retrieved from the storage it is stored within the buffer cache of the system global area. • When the block is deemed no longer needed it is, traditionally, removed from the buffer cache and a new call to the storage is done when it is needed again. B) Flash cache write • When using Smart Flash Cache a block is not removed from the buffer cache however is evicted to the flash cache instead. Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 5
- 6. Oracle Database – Flash Cache Lifecycle A) Storage read • When a block is retrieved from the storage it is stored within the buffer cache of the system global area. • When the block is deemed no longer needed it is, traditionally, removed from the buffer cache and a new call to the storage is done when it is needed again. B) Flash cache write • When using Smart Flash Cache a block is not removed from the buffer cache however is evicted to the flash cache instead. C) Flash cache read • When a block is needed again and is not available in the buffer cache in the SGA it is retrieved (if available) from the flash cache instead. • If a block is not available in the SGA buffer cache AND it is not available in the flash cache, only then a call to the storage is done. Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 6
- 7. Oracle Database – Flash Cache Advantages Advantages • By limiting the number of IO calls to the storage the overall performance of your database is extremely improved. • By limiting the load on your shared storage not only this specific database benefits, all databases and applications that make use benefit due to a lower overall load on the shared storage. Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 7
- 8. Oracle Database – Flash Cache Hardware Available hardware • Flash Cache is (in general) offered via one or more PCIe cards that are seen by the operating system as a separate device. A growing number of vendors are in the market Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 8
- 9. Oracle Database – Flash Cache Implementation Operating system considerations • Generally speaking ALL PCIe flash cards will work on almost every popular operating system including MS Windows, Linux and Solaris. • The database functions used to make use of the Oracle database Flash Cache will ONLY work on Oracle Linux and Oracle Solaris and not on any other operating system Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 9
- 10. Oracle Database – Flash Cache Implementation Operating system device • Generally a flash card will be showing as a device in /dev/ on your operating system. • Example of a EMC VFcache controller card on Linux: • Example of a EMC Vfcache card drive representation on Linux • Depending on the make and model of your card you will have to follow the specific instructions of the vendor to ensure the card is installed on your system in the correct manner. Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 10
- 11. Oracle Database – Flash Cache Implementation Oracle Database implementation • DB_FLASH_CACHE_FILE – • Should point to the location(s) of the flash device(s) to be used. DB_FLASH_CACHE_SIZE – Should state the size (per location) that can be used for flash cache. db_flash_cache_file = /dev/raw/sda, /dev/raw/sdb, /dev/raw/sdc db_flash_cache_size = 32G, 32G, 64G Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 11
- 12. About – Johan Louwers Johan Louwers - Oracle and Cloud Computing I am spearheading innovation within the Capgemini Group by developing the ‘Capgemini Oracle Run’ hosting and computing cloud and ensuring our clients have a completely managed enterprise IT environment. Capgemini Expert on: • Infrastructure Transformation • Cloud Computing • Oracle Technology Contact me: Johan.Louwers@capgemini.com @johanlouwers @CapgeminiOracle http://johanlouwers.blogspot.com http://www.capgemini.com/experts/ oracle-and-cloud-computing/johanlouwers Oracle Database and Flash Cache | JAN-2014 | Johan Louwers Copyright ©2013 Capgemini. All Rights Reserved 12
- 13. About Capgemini With more than 130,000 people in 44 countries, Capgemini is one of the world's foremost providers of consulting, technology and outsourcing services. The Group reported 2012 global revenues of EUR 10.3 billion. Together with its clients, Capgemini creates and delivers business and technology solutions that fit their needs and drive the results they want. A deeply multicultural organization, Capgemini has developed its own way of working, the Collaborative Business Experience™, and draws on Rightshore®, its worldwide delivery model. Learn more about us at www.capgemini.com. www.capgemini.com The information contained in this presentation is proprietary. Copyright © 2013 Capgemini. All rights reserved. Rightshore® is a trademark belonging to Capgemini.