1 / 32

Oracle RAC

Oracle RAC. Overview of Real Application Clustering Features and Functionality. Overview. What is RAC? Cache Fusion Failover and Load-balancing Transparent Application Failover (TAF) Other RAC Features. RAC – What is it?. Multiple instances of Oracle running on up to 8 nodes

natane
Download Presentation

Oracle RAC

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Oracle RAC Overview of Real Application Clustering Features and Functionality

  2. Overview • What is RAC? • Cache Fusion • Failover and Load-balancing • Transparent Application Failover (TAF) • Other RAC Features

  3. RAC – What is it? • Multiple instances of Oracle running on up to 8 nodes • Multiple instances share a single physical database • All instances can simultaneously execute transactions against the single database • Caches are synchronized using Oracle’s Global Cache Management technology (Cache Fusion)

  4. History of Oracle RAC • Previous Oracle Clustering Products • Oracle FailSafe on Windows • OPS (Oracle Parallel Server) on multiple platforms • OPS to RAC: 7.3 OPS  8i OPS  9i RAC  10g RAC • The clustering mechanism used to be more dependent on the Operating System. • With 10g RAC, clustered database is built into Oracle

  5. Oracle RAC Features • Full Cache Fusion • Enhanced coordination of cache management and distributed lock manager (DLM) • Lock simplification and automation • Global Cache Service coordinates local buffer cache and remote block transfers • Enhanced IPC • Resource configuration simplification and automation • Improved cluster aware tools • Enhanced DBCA • Oracle Enterprise Manager and Grid Control Integration Enhancements

  6. Server Server Server Server RAC uses “Shared Everything” Users Database

  7. How RAC clustering is done • One set of data • All nodes in the cluster see the same set of data • All nodes have access • Any node can update the data

  8. Increased Manageability • One virtual system to configure and manage • Single Oracle Database • Single management console • Single system image for the database integrated with the cluster • Cluster-wide monitoring and diagnostics • Oracle Enterprise Manager Integration (9i) • Oracle DBConsole and Grid Control Integration (10g)

  9. What’s shared; What’s not • Shared • Disk access • Resources that manage data • All instances have common data & controls files • Not Shared • Each node has its own dedicated: • System memory • Operating system • Database instance • Application software • Each instance has individual • Log files and • Rollback segments

  10. RAC can perform • Load-balancing • Failover

  11. Client Node 4 Node 1 Node 2 Node 3 Load-Balancing through the Listener Listener Listener Listener Listener Database

  12. Client Node 2 How workload is balanced • Nodes report CPU usage to listeners Node 1 Database

  13. Client Node 2 How workload is balanced • Listeners choose least busy node when request comes in from client Node 1 Database

  14. Node 4 Node 1 Node 2 Node 3 Load-Balancing Users Database

  15. Failover • If a node in the shared disk cluster fails, the system dynamically redistributes the workload among the surviving cluster nodes. • RAC checks to detect node and network failures. A disk-based heartbeat mechanism uses the control file to monitor node membership and the cluster interconnect is regularly checked to determine correct operation. • Reduced time to recovery with concurrent resource configuration and instance (cache) recovery • Enhanced failover reliability in 10g with the use of Virtual IP addresses (VIPs)

  16. Server Server Server Server Failover Users X Database

  17. Transparent Application Failover • Masks failures to end users; they don’t need to log back into the system • Applications and users are transparently reconnected to another node • Applications and queries continue uninterrupted • Transactions can failover and replay • Login context maintained • DML transactions are rolled back

  18. RAC Improvements for Oracle 9i • Full Cache Fusion • Enhanced coordination of cache management and distributed lock manager (DLM) • Lock simplification and automation • Global Cache Service coordinates local buffer cache and remote block transfers • Enhanced IPC (InterProcess Communication) • Resource configuration simplification and automation

  19. Oracle 10g RAC New Features • Integrated Clusterware Management • No third-party clusterware software required • Automatic Workload Management • Application workloads can be managed through named services • Single System Image Management • Enterprise Manager manages RAC instances as a single image • Fast Connection Failover • Fast recovery between the database and mid-tier applications • Performance Improvements • Reduced message traffic, memory usage, and other resources • Zero Downtime Patching • Patches may be applied one node at a time without downtime • Cluster Verification and Improved Diagnostic Tools • New cluster diagnostic tool and improved diagnostic tools

  20. Full Cache Fusion • Is a major feature of RAC starting with 9i • The underlying technology that enables RAC • Protocol that allows instances to combine their data caches into a shared global cache • Allows any node to get the most up-to-date data information from the cache of any other node in the cluster without having to access the disk drives again. • Improved performance with 10g

  21. What is Cache Fusion? When do I care about it? • “Dirty” block of data is created • Data from disk is read into memory on a node • Data is updated on that node • Data hasn’t been written to disk yet. • Another node requests the data

  22. “ABC” block of data written to the disk drives in the database Node A Node B ABC Data

  23. “ABC” block of data read into memory on Node A Node A Node B ABC Data ABC Data

  24. “ABC” updated to “XYZ” in cache Node A Node B ABC Data XYZ Data ABC Data

  25. Node B requests data block I want data! Gimme! Gimme! Node A Node B ABC Data XYZ Data ABC Data

  26. Node A must write data block to disk drive I want data! Gimme! Gimme! Node A Node B ABC Data XYZ Data Previous to 9i RAC write ABC Data XYZ Data

  27. Node B must read data block from disk drive Node A Node B ABC Data XYZ Data XYZ Data Previous to 9i RAC read ABC Data XYZ Data

  28. Now with RAC Cache Fusion I want data! Gimme! Gimme! Node A Node B ABC Data XYZ Data XYZ Data • Data is transferred immediately via the interconnect • Shared cache minimizesslow I/O ABC Data

  29. Cache Cache Cache Cache Server Server Server Server Shared Cache Across Nodes Users Database

  30. Resource Simplification and Automation • No init.ora parameters required • Resource affinity • to move the location of the resource masters for a database file to the instance where block operations are most frequently occurring. This optimizes • Dynamic resource remastering • Ability to move the ownership of a resource between instances of Real Application Clusters. • Dynamic resource remastering is used to implement resource affinity for increased performance.

  31. Review • What does cache fusion avoid that was mandatory in previous versions of Oracle Parallel Server? • Which Oracle process is most important in managing user session failover? • If the purpose of the interconnect is NOT to serve as a “heartbeat”, where is the heartbeat?

  32. Summary • New Features • Shared Everything Clustering • Cache Fusion • RAC Clustering failover & load-balancing

More Related